Part III. Secor. iii. § 2.) | CRETACEOUS.’ 833 
and variety of the reptilian remains, to which reference has been already 
made (p. 810, 811). Some of the earliest types of birds also have been 
obtained from the same important strata. 
No question in American geology has in recent years given rise 
to more controversy than the place which should be assigned to the 
Laramie or Lignitic group, whether in the Cretaceous or Tertiary series. 
The group consists mainly of lacustrine strata, with occasional brackish- 
water and marine bands. While the mollusca in some of the shell- 
bearing beds comprise species of Inoceramus, Anchura, Gyrodes, Cardium, 
Cyrena, Melampus, Ostrea, and Anomia, in others they belong to the modern 
lacustrine and fluviatile genera Physa, Valvata, Cyrena, Corbula, Unio. — 
The abundant terrestrial flora resembles in many respects the present 
flora of North America. A few of the plants are common to the Middle 
Tertiary flora of Europe, and a number of them have been met with 
in the Tertiary beds of the Arctic regions. Some of the seams of 
vegetable matter are true bituminous coals and even anthracites. <Ac- 
cording to Cope, the vertebrate remains of the Laramie group bind it 
indissolubly to the Mesozoic formations. Lesquereux, on the other hand, 
insists that the vegetation is unequivocally Tertiary. The former 
opinion has been maintained by Clarence King, Marsh, and others; 
the latter by Hayden and his associates in the Survey of the Western 
Territories. Cope, admitting the force of the evidence furnished by 
the fossil plants, concludes that ‘there is no alternative but to accept 
the result that a Tertiary flora was contemporaneous with a Cretaceous 
fauna, establishing an uninterrupted succession of life across what is 
generally regarded as one of the greatest breaks in geologic time.” The 
vegetation had apparently advanced more than the fauna in its progress 
towards modern types. The Laramie group was disturbed along the 
Rocky Mountain region before the deposition of the succeeding Tertiary 
formations, for these lie unconformably upon it. So great have been 
_ the changes in some regions that the strata have assumed the character 
of hard slates like those of Paleozoic date, if indeed they have not 
become in California thoroughly crystalline masses. 
The blending of marine and terrestrial formations, so conspicuous in 
the western Territories of the American Union, can be traced north- 
wards into British America, Vancouver’s Island, and the remote Queen 
Charlotte group, with no diminution in the thickness of the series of 
strata. The section at Skidegate Inlet in the latter islands is as follows: + 
Upper shales and sandstones. (Few fossils, the only form re- 
cognized being Inoceramus problematicus.) . : : . 1500 feet 
Conglomerates and sandstones (fragments of Belemnites).  . pape | alee 
Lower shales and sandstones with a workable seam of anthracite 
at the base (fossils abundant, including species of Ammonites, 
Hamites, Belemnites, Trigonia, Inoceramus, Ostrea, Unio, Tere- 
bratula, &c.). ; : ‘ : : ‘ , é oc s3000k 
Volcanic agglomerates, sandstones, and tuffs, with blocks sometimes 
four or five feet in diameter . ‘ : : : . Ur 
Lower sandstones, some tuffaceous, others fossiliferous : s »- 1000 = 
13,000 ,, 
1G. M. Dawson in Report of Progress of Geol. Surv. Canada, 1878-9; J. F. 
Whiteaves, Mesozoic Fossils, vol. i. part i. in publications of Geol. Survey, Canada. See 
- also Mr. Dawson’s Repggt on Geology and Resources of the Region near the 49th parallel ; 
North British Boundary Commission, 1878; Report on Canadian Pacifie Railway, 
Ottawa, 1880. 
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