Ivi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



a single degree of tree-ferns ! " The same distinguished writer alludes 

 further on (p. 291), to the importance of the circumstance of a 

 luxuriant vegetation with a tropical character encroaching so largely 

 on the temperate zones, under the same kind of climate that allows 

 of a limit of perpetual snow of little altitude, and consequent descent 

 of glaciers into the sea. In South America glaciers descend into the 

 sea in lat 46° 30'. The occurrence also of those denizens of the 

 tropics, the humming-birds, at an elevation of 10,000 feet above the 

 sea, and along the western coast of South America from the tropics 

 to the forests of Tierra del Fuego, as described by the same author, 

 is another important fact bearing on this argument which cannot 

 altogether be overlooked. 



These considerations seem to show, that, even admitting the tropical 

 character of the Permian flora and fauna, which however Prof. 

 Ramsay hardly does, there is no improbability of their juxtaposition 

 with glaciers in lat. 5 1°, at a period too when we are unacquainted with 

 the relative distribution of land and sea. It appears to me, however, 

 that the strongest argument against Prof. Ramsay's theory, is to be 

 derived from his own account of the breccia-bed itself. Without 

 giving the exact thickness of this bed in any locality, the vast extent 

 of country over which it is distributed, amounting according to the 

 author's own calculation to an area of 500 square miles, and distributed 

 moreover with great regularity, militates strongly against the glacial 

 theory. In ordinary cases we find the glacial detritus either collected 

 in vast irregular heaps or monticules at the termination of the glacier, 

 or distributed in long parallel lines or ridges, of many miles in length, 

 along the edges of the glacier, marking the limit of its action, and 

 accurately defining its extent. I am not aware that the transported 

 matter of glaciers is ever found spread out with the regularity of a 

 real subaqueous formation, as has been the case with these Permian 

 breccia-beds ; and even admitting some of these breccia-beds to have 

 been transported by the agency of icebergs floating across the waters 

 and transporting the detritus from a neighbouring shore, the great 

 extent of the beds in question would almost equally preclude the pro- 

 bability of such a solution of this remarkable deposit. Vast debacles 

 occasioned by the sudden burstings of the barriers of an extensive 

 inland lake, or violent disturbances of the ocean by the elevation of 

 mountain chains or the sea-bottom, many instances of which must 

 have occurred in various periods during the palaeozoic age, appear 

 to me a more simple and satisfactory mode of accounting for the 

 diff'erent phaenomena described by Prof. Ramsay. During the violent 

 commotion caused by such an agency, the huge masses of rock, accom- 

 panied by a sea of mud, would be hurled against each other, and the 

 sharp angles of the disrupted masses might easily impress on the 

 sides of transported boulders those striae and scratches which have 

 given rise to the theory of their being due to glacial action or to 

 icebergs. The subject, however, is an interesting one, and we may 

 hope that the further progress of the Geological Survey will throw 

 additional light on the causes of the phaenomena described by the 

 author of this paper. 



