86 REPORT—1850. 
» 
more powerful Gulf-stream into an easterly course, and would go sweeping over the 
submerged land in the direction indicated by the grooves and scratches, bearing with 
it every spring its many thousand gigantic icebergs, and its fields of sheet ice many 
hundred square miles in extent. And these, by grinding heavily along the buried 
surface, would gradually wear down the upper strata of the softer formations, leaving 
the clay which they had thus formed to be deposited over, and a little to the east of 
the rocks that had produced it. It is in further accordance with the theory, that in 
this part of the country the deeper deposits of the boulder clay occur on the eastern 
line of coast. 
Mr. Miller, at the close of his paper, exhibited a collection of Boreal shells, with 
fragments of oolitic fossils, chalk, and chalk flints from the boulder clay of Caithness, 
and referred to the meritorious labours of Mr. Robert Dick of Thurso, the original 
discoverer in that county of the oolitic fossils and the chalk, and the collectcr of most 
of the shells. 
On the Discovery of Paleozoic Fossils in the crystalline chain of the Forez in 
France, and on lines of dislocation between the Lower and Upper Carbo- 
niferous Deposits of France and Germany. By Sir RopErick Impey 
Mourcuison, President of the Section. 
During a visit this summer to the baths of Vichy, in the department of the Allier 
(France), the author had great pleasure in revisiting the tertiary lacustrine deposits 
of the Limagne d’Auvergne, which occupy the low and undulating country between 
the mountains of the Puy de Dome on the west, and the Forez on the east. He was 
also led to pay some attention to the structure and age of the last-mentioned cry- 
stalline chains. No French geologist had noted the occurrence of a fossil in them, 
but on his first visit to the banks of the Sichon, a tributary of the Allier, Sir Roderick 
discovered that certain peculiar and hard grits of the tract contained encrinites, 
and in a second examination he further detected in the schists a few remains of bi- 
valves, univalves, trilobites, and corals. The form of one of the best preserved of these 
bodies has a resemblance to a Silurian Lepteena, or Chonetes ; but the occurrence of 
a Productus of a form very nearly allied to P. fimbriatus (Sow.), (identified by M. 
de Verneuil), leaves no doubt that the deposit belongs to the lower part of the 
carboniferous epoch. Another fossil resembles the palzozoic Cypricardia, but ap- 
proaches nearest to the Pleurophorus costatus (King) of the Permian system, A 
portion of the head of a Trilobite belongs to the genus Philiipsia (Portlock), so cha- 
racteristic of the British mountain limestone; and thus the age of these rocks is 46- 
termined. In the geological map of France these strata are placed as old transition 
and crystalline ; and for such, or for the lowest Silurian rocks, they might un- 
questionably very well have passed, if lithological structure and aspect had alone de- 
termined their age. 
The slaty schists, porphyritic grits and other varieties of the sedimentary portion of 
these rocks, as well as the various porphyries by which they are penetrated, are 
indeed well depicted by M. Dufrenoy in the ‘ Mémoires pour setvir’ ; and the very 
locality in question was specially described by M. Visquesnel*. These authors having 
never observed fossils, and judging from mineral character only, naturally assigned 
too high an antiquity to the rock. Sir Roderick having ascended the Sichon from 
the castle of Busset for some leagues to near its source (Ferriéres), found that owing 
to the eruptions of the porphyry (often very granitiform) the schistose rocky grits 
were usually so metamorphosed and dislocated, that he was wholly unable to 
attempt to define anything like a descending series from the above-mentioned lower 
carboniferous rocks to others which might be considered Devonian and Silurian. 
Besides fossils, he observed two thin bands of scaly, hard, subcrystalline limestone, 
associated with the schists of Cusset. In truth, the limestones increase in volume near 
Ferriéres, where they are in the state of marble, of grayish, reddish, veined, and even 
of white colours. In order to satisfy himself whether the loftier and bolder portion 
of the chain of the Forez belonged to the same class of rocks as those he had ex- 
amined in its lower and northern end, Sir Roderick made an excursion to Thiers. 
There he recognized precisely the same phzenomena (but on a grander scale, and in 
* Sur les environs de Vichy, Bull. Soc, Géol. France, vol. iv. 1st series, p. 145. 
