58 GEOLOGY OF THE DENVEB BASIK 



employed in the present instance in fixing the taxonomic rank of the portion 

 of the Red Beds under discussion, and, in addition, as evidence of the pro- 

 priety of dividing the entire series into two distinct -roups, thus establishing 

 in the West the same di\ ision for the New Red sandstone as is held in Europe. 

 Additional evidence for such division, as well as some, in the nature of 

 plant life, opposed to it, is found in the developments by Professors Scudder 

 and Lakes, at Fairplay, Colo. 3 In the Red Beds of this locality Professor 

 Scudder discovered several species of cockroaches, the affinities of which 

 led him to regard die beds with no little positiveness as Triassic. .V sum- 

 mary of his argument is as follows: First, there exists a distinct difference 

 between the Fairplay species of cockroaches referable to different genera 

 ot the Palseoblattarise, or Paleozoic cockroaches, and any species hereto- 

 fore known in the Paleozoic belonging to the same genera; second, there 

 is the presence of two new genera and several new species belonging to 

 the Palseoblattarise, the former either notably different from any of their 

 other genera or, with certain affinities for the associated new species 

 belonging to one of the genera of this family already known, but which 

 ha\e a marked difference from the known species of that a'eiius; third, the 

 smaller size of die Fairplay cockroaches as compared with the Paleozoic 



forms, and their close agreement in this respect to European Mesozoic 



cockroaches — a fact that has much value; fourth, the presence of several 

 cockroaches not belonging to die Palseoblattariae, and closely allied to the 

 Jurassic forms of England — so much so, indeed, that several of them, at 

 least, would lie at once recognized as such l>\ anyone familiar with the 

 forms already known from the formation in England; fifth, the entirely 

 different aspect of all the latter from any and all Paleozoic forms. 



Professor Scudder sums up his remarks thus: "They show a commin- 

 gling of strictly Jurassic forms with a larger proportion of types w Inch may 

 l>e called Upper Carboniferous or Permian with a distinct Jurassic leaning. 

 There i*-. therefore, a strong probability that the hods in which thev occur 



belong to tin 1 intermediate formation, the Trias." Moreov* r, the insects 



found at Fairplay are two-thirds as abundant in species as the plants, which 



1 



1 Triassic insects from the Rocky Mountains, bj Samuel 11. Scudder, Am. Jour, Sci. (3), Vol. 

 XXVIII, p. 199; < 'ii some specimens of Permian fossil plants from < 'olorado, 1>\ Leo Lesqnereux, I 'nil. 

 Miis. Comp. Zool., Earvard College, Geol. Ser. I. Vol. VII, ]>. 243. 



