142 EXPLORING EXPEDITION FROM SANTA FE 



widely separated by its general habit; yet, if the nervation and mode of insertion on 

 the racing of the pinnules afford good characters for generic classification, it must be 

 grouped with these. 



By Unger and Goeppert the genus Oto/samites is not recognized, and our fossil 

 would be classed by them in Zamites. Brongniart, however, claims that the section of 

 Zamites represented by Otozamiti's, Br., including species differing much among them- 

 selves, it is true, biit having in common important botanical characters, may be very 

 properly regarded as forming a natural generic group. 



As this species is distinctly new, it affords no very reliable evidence by which to 

 judge of the age of the formation in which it is found, and yet it was with very lively 

 pleasure that I discovered this and the associate Cycad in the copper-mines of New 

 Mexico. Extremely few fossils had been found at this horizon, although I had sought 

 them most carefully over a large area in which the red sandstones and shales are 

 exposed. On finding in the old copper-mine at Abiquiu great numbers of fossil plants, . 

 I was more than pleased, and when upon examination they proved to be Cycads, 

 plants most characteristic of the Triassic and Jurassic rocks in the Old World, I felt 

 that we had here new and important evidence that the criteria of palaeontology may 

 be trusted. 



Among the Cycads of the Old World, the species most nearly allied to Oto. J\Ia- 

 comlii is perhaps 0. obtusa, Lind. & Hutt. (vol. 2, p. 128), from the Lias of England, 

 and yet it will be seen on comparison of the two species that they are quite distinctly 

 separated. 



The discovery of this species by Mr. Remond in Sonora, associated with well- 

 marked Triassic fossils, is a fact of great scientific value, and of very special interest 

 to me, as it proves that the entire thickness of the gypsiferous red sandstones and 

 marls of New Mexico, on and west of the Rio Grande, is made up of strata as old as 

 the Trias. There is no doubt of the existence of Jurassic rocks in the Rocky Mount- 

 ain region; but, so far as yet known, they do not occur on any part of the route fol- 

 lowed by M. Marcou, and where he claims to have discovered them. 



The plant-beds of the Moqui villages and Abiquiu are overlain by the yellow 

 sandstones of the Cretaceous formation, and angiospermous leaves were found by us 

 in a number of localities within five or ten feet of the underlying red marls. On the 

 east flank of the Rocky Mountains, in some places, as at Cold Spring, on the Santa Fe 

 road, I found a series of calcareous strata interposed between the Gypsum formation 

 and the Cretaceous sandstones, and these, since holding the place and having the 

 lithological character of the beds found by Dr. llayden a little farther north, contain- 

 ing Jurassic fossils, are probably, of that age. It is, however, true at the present 

 time that no Jurassic plants have been found on this continent. 



Formation and locality. Triassic strata: Abiquiu, New Mexico; Los Bronces, Sonora 

 (Mr. Remond); Yaki River, Sonora (Mr. Hartley). 



ZAMITES OCCIDENTALS, Newb. 



Plate V, figs. 1, 1", 2. 



Frond petioled, linear-lanceolate; pinnules springing from the rachis at an 

 angle of about 45, rigid, coriaceous, closely approximated, linear in outline, 6-15 



