Between the city of Chihuahua and El Paso del Norte the physical and lithological features of the cantera still prevail. The road lies over the plain of Encenillas-one of the typical valleys above described, extending, together with its bordering mountains, within twenty miles of the Rio Grande where limestone hills are again met with, forming the bluffs of the valley. This limestone seems to bear the same relation to the cantera as the Cretaceous beds at Presidio del Norte below. Hence I must take exception to the determination of this limestone by Dr. Wislizenus as Silurian, especially as this was upon the inadequate evidence of an "injured and imperfect" coral which he refers to Calamopore, and a bivalve shell of the genus Pterinea. I did not stop to collect fossils at this locality, no question having been present to my mind on the spot as to its equivalency with the Cretaceous as elsewhere observed, and as I was not then acquainted with Dr. Wislizenus's report.* The discrepancy be tween the lithological terms employed by Dr. Wislizenus and myself proceed from a difference of observation and reasoning. The cantera, (which term I have employed for short) whose characteristic and varying qualities have been detailed, and which has been described as a surface metamorphic formation, horizontally bedded and comparatively undisturbed, attaining a thickness of over 1700 feet, where found within the range of my observation least reduced by denudation (at Cusihuiriachic), and overspreading the middle and northeastern part of Chihuahua, and probably also the western part, Dr. Wislizenus designated generally as porphyry, and sometimes as granitic, and again as trachytic. That what he thus terms is really the so-called cantera, under its various aspects, is clear from his specifying the building stone used in the city of Chihuahua, from which I have taken its local name, as white por phyry, as well as from the fact that he distinguished as granitic and porphyritic its continuation on either side of the El Paso road. He similarly characterized the rock which forms the mountains of Cusihuiriachic, seventy-nine miles west of the city of Chihuahua. Thus it will be seen that in this respect our observations agree as to the extent and identity of the mountain formation, but that we differ as to its origin and lithological character. The orographic features of the country as phenomena of denudation have not been noticed by this traveler. And the determination of the limestone twelve miles N.E. of Chihuahus (Santa Eulalia) as Silurian upon the insufficient evidence of simple specimen, received at second hand, containing "some chambers of an Orthoceras," cannot be accepted in the light of *Memoir of a Tour to Northern Mexico, connected with Col. Doniphan's Expe dition in 1846-7. Senate Doc., Misc. 26, 30th Cong. 1st Ses. See also Report d Dr. Parry: Mex. Bound. Surv., vol. i, Pt. 2d, 8, 9. On the Silurian in the Rocky Mts, see a notice by Prof. J. D. Whitney, Proc. Acad. Nat. Sc., iii, 307. the significant evidence above brought forward to prove the Cretaceous age of the same limestone. In the geological sketch given by Dr. Wislizenus, the formations are laid down according to his description.* The number of Cretaceous fossils collected by myself west of Presidio del Norte, quite disproves the position of Dr. Parry, viz., that the "natural boundaries of this basin (near Presidio del Norte) consist of irregular mountain ranges composed principally of carboniferous limestone similar to that seen above (near El Paso.) But Dr. Parry in this matter seems to follow Prof. Hall who referred the limestone of this section to the carboniferous exclusively on the ground of the lithological analogy with the Carboniferous limestone in numerous western localities, of a simple specimen from the rapids of the Rio Grande, in which no fossils could be recognized. With regard to the "compact and vesicular lavas, and volcanic and friable breccias, etc.," thus termed by Prof. Hall, in the collection of Dr. Parry, it is proper to suggest the former to be referable to the cantera in some of its aspects of coloration, aggregation, and weathering, and the latter to be the cemented rubble above noticed. The limestone back of Presidio del Norte, unmistakably Cretaceous, is brought to the surface by the Conchos axis of elevation, which is so prominent till cut through at the bend of that river, and which does not finally expire for yet a distance of some seventy miles to the southwest. Topographically as well as stratigraphically, this is the lowest part of the state which I visited, and the only part I found either not overspread with, or bearing on its heights, the cantera, which even along the easterly development of this axis, it will be understood, has disappeared but from a narrow belt. The extension of the fossiliferous Cretaceous so far up toward the summit of the Cordilleras, has an important bearing upon the occurrence of Texas Cretaceous fauna in Sonora, where they were found by the late Mr. Rémond. Prof. Gabb, to whom we owe this identification, calls attention to the discovery as going to show a "water communication between the great Cretaceous sea that covered so much of what is now the central portions of our continent, on the one side, and the Pacific, on the other." The recognition of the Cretaceous near Arivechi in Sonora, according to Mr. Gabb, proved only the second reported locality * We much incline to doubt whether Fremont, Stansbury or Wislizenus have brought unequivocal Silurian rocks or fossils from several points in the Rocky mountains. See an editorial critique on a geological map by Jules Marcou (this Journal, vol. xvii, p. 202), by him attributed to Prof. Hall (Geol. North America, two reports, etc., 1858, pp. 93 and 98.) Mexican Bound. Surv., i, Pt. 2d, p. 50. of its occurrence in the whole area of Mexico, the other being in the State of Puebla.* So important a discovery as the occurrence of rich silver deposits in the fossiliferous, as well as the metamorphic Cretaceous of Chihuahua, cannot adequately be treated within the scope of a general article; and I therefore reserve for a subsequent number of this Journal, descriptions of the interesting silver mining localities of Santa Eulalia, Cusihuiricahic and Cieneguilla, of which incidental mention has already been made.+ Although the metamorphic Cretaceous is, through the labors of the Geological Survey of California, well known in numerous localities in the Coast Ranges, as a seat of gold deposits; and the Jurassic, east of the High Sierras within the territory of the United States, as a seat of silver deposits, the instances above given of the unequivocal fossiliferous Cretaceous, as well as a probable metamorphic and later zone of the same series, as sources of silver ores, are the first in North America yet reported. The only parallel occurrence yet brought to light, so far as I am aware, is in Chili, where according to Mr. Rémond, calcareous fossiliferous Cretaceous strata carry silver deposits, evidently much in the same way as at Santa Eulalia. New York, Aug. 10, 1869. ART. XXXVIII.-Contributions to Zoology from the Museum of Yale College. No. IV.-Abstract of a Notice of the Crustacea collected by Prof. C. F. Hartt, on the coast of Brazil in 1867; by SIDNEY I. SMITH. THE paper of which the following is a short abstract, was printed during July and August, in the second volume of the Transactions of the Connecticut Academy, but the whole edition, excepting a few copies of the first two signatures which had been distributed, was destroyed by fire in September last. During the delay consequent to the reprinting of the Transactions, this article seemed desirable. The collection, although quite small, is of interest from the large proportion which it contains of species heretofore known only from Florida or the West Indies. The following is a list of the species with the localities at which they were collected by Prof. Hartt. *Geol. Surv. of California, Palaeontology, ii, p. 257. These three localities have produced during the last 150 years from 200,000,000 to 300,000,000 of dollars, mainly during the last century. Proc. Cal. Acad. of Sc., iii, 1866; Phillips' Mining and Metallurgy of Gold and Silver, p. 318; Domeyko, Ann. des Mines (4), ix, 22. Milnia bicornuta Stimp.-Reefs of the Abrolhos. Mithraculus coronatus Stimp. แ Xantho denticulata White.— Chlorodius Floridanus Gibbes.-" Panopeus politus Smith (Proc. Bost. Soc. Nat. Hist., vol. xii, p. 282, 1869; Trans. Conn. Acad., vol. ii, p. 3, plate i, fig. 4).— Reefs of the Abrolhos. Panopeus Harttii Smith (Proc. Bost. Soc. Nat. Hist., vol. xii, p. 280; Trans. Conn. Acad., vol. ii, p. 5, plate i, fig. 5).—Reefs of the Abrolhos. Eriphia gonagra Edw.-Reefs of the Abrolhos. Callinectes Dance Smith (Trans. Conn. Acad., vol. i, p. 7; Lupa diacantha Dana; non Lupa diacantha Edw., nec Calli; nectes diacantha Stimp.).-Pernambuco and Bahia. Callinectes ornatus Ordway.-Caravellas, Province of Bahia. Goniopsis cruentatus De Haan.-Reefs of the Abrolhos. Cryptograpsus cirripes Smith (Trans. Conn. Acad., vol. ii, p. 11, plate i, fig. 3).-Rio de Janeiro (Coll. Peabody Acad. Sci.) This species differs from the C. angulatus Dana, heretofore the only known species of the genus, in having the front as seen from above nearly straight instead of deeply bilobed, in the much greater breadth of the carapax between the outer orbital teeth-the ratio of this breadth to the breadth of the carapax being 1:143, while in C. angulatus it is 1:1.68,—and in having the posterior legs densely ciliated. Length of carapax in a male, 31.0mm; breadth of carapax, 35.6mm. Uca cordata (Cancer cordatus Linn.)-Bahia. Petrochirus granulatus Stimp. Calcinus sulcatus Stimp. แ แ แ Clibanarius vittatus Stimp-Caravellas, Province of Bahia. Clibanarius sclopetarius Stimp.-Caravellas River. Clibanarius Antillensis Stimp.-Reefs of the Abrolhos. Scyllarus æquinoxialis Fabr.-Bahia. Panulirus echinatus Smith (Trans. Conn. Acad., vol. ii, p. 20). This species is closely allied to P. guttatus, but differs from the figures and descriptions of that species, in having the spaces between the spines of the carapax tuberculose and hairy instead of smooth, the third pair of thoracic legs extending beyond the second instead of the second being longer than the third, and the trausverse sulcus of the third abdominal segment interrupted in the middle. In the posterior thoracic legs of the female, the dactylus is short and armed on the posterior side of the base, with a stout process which closes against a similar process from the extremity of the propodus, both processes being hairy on the outside, and having horny spoonshaped tips.-Pernambuco. Alpheus heterochelis Say.-Reefs of the Abrolhos. Palomon Jamaicensis Olivier.-Penêdo, Rio Sao Francisco. Palemon ensiculus Smith (Trans. Conn. Acad., vol. ii, p. 26, plate i, fig. 2.-Pará.) Rostrum very long, strongly curved downward for the basal half of its length, the terminal half very slender, nearly straight, but strongly inclined upward, armed above with nine to twelve short teeth of which seven or eight are on the basal portion, and the others near the tip, and below with eight to twelve teeth. Second pair of thoracic legs in the male very long and quite slender, in full grown specimens, the merus reaching beyond the tip of the antennal scale, and all the segments to the base of the fingers closely beset with short spinules; hands cylindrical, not swollen, the fingers slender and sparsely clothed with short, downy pubescence; in the females and young the second pair of legs smaller and much less spinulose. Penultimate segment of the abdomen long and narrow, the length above being twice as great as the breadth; terminal segment narrow and tapering regularly to a very slender and acute point. Length, 65 to 100mm. Peneus Brasiliensis Latr.-Bahia. Xiphopeneus Smith, gen. nov., (Trans. Conn. Acad., vol. ii, p. 27). Carapax much as in Peneus, but the rostrum very long and slender, and the gastro-hepatic sulcus scarcely perceptible, while the cervical and branchio-cardiac sulci are distinct. Lamelliform appendages on the inside of the peduncle of the antennulæ very small, not expanded over the eye as in Peneus; anten- ! nulary flagella very long and slender, the upper ones much stouter and longer than the lower. Antennæ, maxillipeds and the three anterior pairs of thoracic legs nearly as in Peneus. Fourth and fifth pairs of legs very long, the terminal segments very slender and flagelliform. Xiphopeneus Harttii Smith (Trans. Conn. Acad., vol. ii, p. 28, plate i, fig. 1.)-Caravellas, Province of Bahia. Rostrum as long as, or considerably longer than the carapax, wholly unarmed below, but the basal portion with a thin carina above, which extends back upon the carapax and is armed with six sharp teeth, the terminal portion is subcylindrical, unarmed, and tapers to a very slender point far in front of the antennal scales. Upper flagellum of antennula |