310 Dr. Carl Ochsenius — On Metalliferous Deposits. 



aware of a figure or specimen in wliicli it has been shown to be 

 present.^ 



Taken as a whole the specimen that I have named Archaastacus 

 Willemoesii resembles the form of the recent Polycheles as neai'ly as it 

 does that of the ancient Eryon, and in the breadth of the pleon and 

 the absence of its dorsal carina, it exhibits conditions that demon- 

 strate a no very distant departure from the modern genus Astacns, 

 which would be more appreciated, if, instead of being dorsally 

 depressed, it had a stronger lateral compression, more especially as 

 relates to the carapace. 



It therefore appears to clearly demonstrate that the genus Eryon 

 has departed from an unknown ancestor of Astacus, and that the 

 recent Polycheles is in direct descent from Archceastacus of the 

 European Lias.^ 



V. — Metalliferous Deposits. 



Ey Carl Ochsenius, Phil. Dr. Sc. Geolog. and Geogr., 

 of the University of Marburg. 



THE origin of metalliferous deposits has long been a subject of 

 discussion. Professor Joseph Le Conte, however, seems to have 

 arrived at a very decided opinion on this question, for in a contribu- 

 tion to the " American Journal of Science" (3rd series, xxvi. p. 1 — 

 19, July, 1883), after referring to Sulphur Banks and Steamboat 

 Springs in California, he says : " Thus then subterranean waters of 

 any kind, but especially alkaline, at any temperature, but mostly 

 hot, circulating in any direction, but mainly upcoming, and in any 

 kind of waterway, but mainly in open fissures, by deposit, form 

 metalliferous veins." 



At the meeting of the German Geological Society in the month of 

 August, 1881, the formation of metalliferous veins was treated by 

 me as being one of those phenomena which must be attributed to 

 the action of mother liquor salts ; the following are translated ex- 

 tracts from the journal of that Society.^ 



" As a consequence of my investigations concerning rock salt beds 



^ The scale at the base of the outer antenna in Eryon Barrovensis, M'Coy, is 

 figured by Dr. H. Woodward (see Quart. Journ. Gaol. Soc. 1866, vol. xxii. pi. xxv. 

 fig. 1) from specimens in the British Museum and the collection of the Eev. P. E. 

 Brodie, F.G.8. Dr. Woodward writes: — "Each of the outer antennae has a large 

 oval scale attached to its broad basal joint" {op. cit. p. 496). — Edit. 



' Whatever decision may ultimately be arrived at, as to the advisability, or other- 

 wise, of abolishing the genus Eryon, and adopting Mr. C. Spence-Bate's proposed 

 genus Archceastacus, for these Liassic Crustaceans, there is little doubt that the 

 specimen here described as A. Willemoesii is the same as Eryon crassiche/is, H. 

 Woodw., 1866, Quart. Journ. Geol. Soc. vol. xxii. p. 497, a reduced figure of which 

 only was given on pi. xxv. fig. 2 {op. cit.), in which the characters are not well 

 shown. Capt. Hussey's specimen figured as E. crassichelis is moreover preserved 

 with the underside exposed, whereas Mr. J. E. Lee's specimen exhibits the dorsal 

 aspect. The detached carapace of E. crassichelis, from Mr. Day's Collection (see 

 op. cit.), now in the British Museum, appears, however, identical with Mr. Lee's 

 specimen. In Mr. Day's specimen the eye can also be detected. — Edit. 



3 Zeitschrift der Deutschen geologischen GeseUschaft, 1881, 507 — 511; 1882, 

 288—372. 



