186 PROCEEDINGS OF THE GEOLOGICAL socinry. [Jan. 12 
Messrs. Riley and Stutchbury in the year 1836, the additional 
interest now attached to these remains being due to fresh re- 
searches, by Prof. Huxley, into the history and distribution of the 
Dinosauria through the lower Secondary rocks of the globe. It 
therefore becomes a matter of interest, if not necessity, to fix 
the geological age of the reptilian remai the more so, in this case, 
on account of the numerous opinions held by Continental and Bri- 
tish geologists as to the exact equivalents of this conglomerate, and 
its place in the Triassic group. 
9, LOSITION Ih ME OF H D) N OF OLOMITI ONGLOMERATE., 
6: 2 ION IN TIME OF THE RuEpriLrAN orn DoLomrrie C LOMERATE 
Tt is at all times difficult, if not, perhaps, almost impossible, to 
assign an approximate age to remains found in an extensive, conti- 
nuously and contemporaneously forming and associated conglomerate 
belonging to any age or deposit; it is especially so with the Dino- 
sauria under consideration ; ; and whether they inhabited any certain 
or given area, or at any given period during the immense lapse of 
time these magnesian breccias were under accumulation, is a pro- 
blem important to solve, both as to space and time,—the first as 
bearing upon the habitat, locality, or area occupied by these genera 
prior to, and at the time of their deposition; the latter as affecting 
their relation to that particular horizon of the conglomerate, and 
the assignment to these remains of an earl y or late date in rela- 
tion to the mass. ‘Two great periods of oscillation and associated 
phenomena have been een to the area under notice,—the first 
a downward movement of the palcozoic land with its consequent 
loss of material, which must have commenced after its consolidation 
and elevation to the position it occupied at the time the New-Ked 
sea began to denude its mass, and lasted through the whole of that 
long pericd of depression which was sufficient to allow of fully 
1000 feet of New Red marl and sand to be deposited over the de- 
pressed paleeozoic rocks. The second per riod was one of elevation, 
during which the accumulation of the first period was again partly, 
if not almost entirely, denuded or removed (this is of comparatively 
recent date); and this again exposed the old land-surfaces, nearly as 
we now see them. Certainly, then, at some period during the depres- 
sion and accumulation of the dolomitic conglomerate these reptilian 
remains were deposited; and it is equally certain that these two 
genera (Vhecodontosaurus and Palceosaurus) inhabited the area or 
region where found. 
The occurrence of these Triassic Dinosauria at the elevation of 300 
feet above the present sea-level, and on the general tableland now oc- 
cupied by the Carboniferous Limestone, and apparently that portion of 
it last influenced by the New-Red sea, would lead me to infer that it 
vas late in the history of the Keuper that their deposition was effected. 
I assume this from the different stages and relative levels now 
occupied by the conglomerate, which necessarily elucidate their 
position in time at the date of deposition. The whole period of 
elevation is measuted by the successive steps and stages occupied by 
