BLAKE — DISTRIBUTION OF MASTODON. 



469 



The basalt, which at last ended the work, and caused the abandon- 

 ment of the enterprise, is a sub-crystalline greenstone, rudely 

 columnar at its near-lying outcrop, and containing in places vertical 

 series of spheroids, which show their progress of change, by com- 

 pression in a heated state, into columns. It may be called a horn- 

 blendic greenstone. One interesting feature of it is the quantity 

 of unaltered calcite it contains, disposed in embedded amor- 

 phous masses in some cases as large as an orange. Zeolitic 

 crystals also occur in it. In the dyke, which is extensively quarried 

 for nearly a mile, these features are well to be seen ; but a visit 

 should also be made to the northerly limit of the outburst, Munster's 

 Hill, which the basalt has capped with " a wild-looking pile of rhom- 

 boidal rocks, intensely black and hard ; a mass not concealed by dross 

 and rubble, as at other parts of the line, but lying naked to the 

 light, hid by nothing but the grey crust of lichens.' 1 * These amor- 

 phous, rudely-columnar masses have a great resemblance to those 

 which cap the Titterstone Hill, and there form the " Giant's Chair." 



I do not know of a wilder spot in Worcestershire than Munster's 

 Hill. A clump of immense yews are rooted at the feet of the basaltic 

 columns, and lie against them, clasping the rugged masses with 

 brown gnarled arms as ancient-looking as the rock itself. 



Comparison of the Shatterford basalt with that of Kinlet, four 

 miles westward, is an instructive work. At the latter outburst the 

 Plutonic rock is of the same general character, that of hornblendic 

 greenstone, but it contains crystals of augite and many vitreous 

 crystals of calcite ; weathers white, and is rudely columnar, like the 

 Shatterford rock. 



ON THE DISTRIBUTION OF MASTODON IN SOUTH 

 AMERICA. 



By Charles Carter Blake, Esq. 



One of the greatest and most significant laws which modern palaeon- 

 tology has unfolded to us, is that principle by which it is definitively 

 ascertained that, as a general rule, the animals of the Post- Pliocene, 

 and indeed all the later Tertiary ages, were restricted to the same 

 great geographical provinces as their representatives in the existing 

 fauna. Amongst the Pliocene Mammalia of South America, we find 

 the same preponderance of the Edentata, the same family of prehen- 

 sile-tailed Monkeys, and the same typical Llamas and Vicunas, as we 

 find in the present pampas of La Plata, forests of Brazil, or elevations 

 of the Andes. 



* Rocks of Worcestershire, p. 29. 



