TBANSACTIONS OF THE SECTIONS. 63 



evidently belonged to it ; they were described as conical, slightly curved, pointed, 

 and finely striated, Ij inch long by ^ inch in diameter ; also other smaller ones, 

 only three eighths of an inch by one eighth and a half. The characteristic 

 sculptured surface of the bone was well preserved on the detached jaw, and obser- 

 vable on several parts of the head. A portion of the body, consisting of displaced 

 vertebrffi and ribs, with some larger bones (probably humerus, ilium, and other 

 bones of the fore and hind limbs), were scattered over the slab ; the termination of 

 the body and tail was unfortunately deficient. 



The bones were not in a very satisfactory state for study. Some of the verte- 

 brae possessed their spinous processes (neurapophi/scs) and exhibited their concave 

 articular surfaces ; in others the cetitra only were preserved ; these were about an 

 inch long and half an inch in breadth, the spinous processes being from I5 to 

 2 inches in height and J inch wide at their upper and widest part. The longest 

 lib measured about 65 inches with the curve, being f inch broad, a slight gi-oove 

 traversing its length ; the ju'oximal end shows the double articulating portions, 

 ctqntulum and tubercidmn. In the group of ribs and vertebrae fi-oni the same col- 

 liery, before alluded to as being in the JBritish Museum, one of the ribs measured 

 Q\ inches with the ciuwe and J inch in breadth, showing it to have belonged to a 

 much larger animal. 



The extreme length of the head is about 14 inches, measuring from the snout to 

 the tympanic bone ; its height from the lower portion of the under jaw to the 

 supraoccipital is Og inches, being in the proportion of two thirds to the length. 

 The total length of the specimen is about 3 feet ; this does not, however, represent 

 any thing like that of the entire animal when complete, which must have been at 

 least 6 or 8 feet long. 



The condition of the fossil, which is impressed upon two large slabs of anthracite 

 coal (obverse and reverse of the same specimen), is not at all favourable for exact 

 determination, and it is much flattened by pressure. 



On tlie Action of Ice in wTiat is usually termed the Glacial Period. 

 By the Eev. James Bkodie. 



It is generally supposed that there was a lengthened period intermediate between 

 the tertiary and the quaternary eras, when a great part of the earth was subjected 

 to extreme cold. This has been called the Glacial Period or Great Ice Age. 

 The facts adduced in support of these conjectm-es are : — 



Traces of glacier-action have been foimd in regions which now enjoy a 



temperate climate ; 

 Boulders, evidently transported by glacial currents from northern regions, 

 ai'e found in temperate localities. 



My reply is, that these discoveries prove that in former times there must have 

 been great cold in places which are now comparatively warm ; but they do not 

 prove that that cold was contemporaneous over all the quarters where these traces 

 are found. When the climate was cold in one place, there is every reason for sup- 

 posing that it was warm in others. 



Glaciers are rivers of ice ; they come down from the mountain-side ; but they are 

 fed by the vapours that are principally raised by the action of the sun on the in- 

 tertropical seas. If the area from which that vapour is raised be diminished, the 

 vapour will be diminished; and if vapour is not supplied, no glacier can be 

 formed. 



Glacial currents come from the polar regions ; but they would cease if counter- 

 currents from the equator did not bring up water to supply the place of that which 

 they carry away. 



It has continued its uninterrupted onward course, the cold gradually increasing 

 in intensity, down to the present day. 



