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."* 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 DISTKIBUTION OF MASTODON IN SOUTH 
AMERICA. 
By Charles Carter Blake, Esq. 
One of the greatest and most significant laws which modern palagon- 
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 Yicuiias, as we 
find in the present pampas of La Plata, forests of Brazil, or elevations 
of the Andes. 
* Kocks of Worcestershii-e, p. 29. 
