34 THE GEOLOGIST. 
as nowadays tlie Vicugna prefers the mountains, \\\nie its larger congener the 
Guanaco roams over the Patagonian plains. 
Lastly it was remarked that, as Macrauchenia was an animal combining, to 
a much 'more marked degree than any other known recent or fossil mammal, 
the peculiarities of certain artiodactyles and perissodactyles, and yet was cer- 
tainly but of post-pleistocene age, it 'presents a striking exception to the com- 
monly asserted doctrine that " more generalized" organisms were confined to 
the ancient periods of the earth's history. Tor similar reasons the structure of 
the MacrciKcheiiia is inimical to the idea that an extinct animal can always be 
reconstructed from a single tooth or a single bone. 
" On the Palaeozoic Fossils brought by Mr. D. Forbes from Bolivia." By 
J. ^\. Salter, Esq., P.G.S. 
The fossils of Carboniferous age brought home by Mr. Forbes are the well- 
known species described by D'Orbigny. Several are identical with Eui'opean 
forms (as Productus Martini, &c.), and are cosmopolitan ; others are peculiar 
to the district {Spirifer Condor, Orthis Andii, tc). 
Mr. Forbes has brought a "Devonian" trilobite (Phaeops latifrons or Ph. 
b?ffo), in a rolled pebble, from Oruro : it is a widely-spread species. Another 
allied form was found by Mr. Pantland, many yeai's back, at Aygatchi. in 
other respects the " Devonian" evidence is scanty. 
In Mr. Forbes' fine collection of Silurian fossils none of D'Orbigny's ten 
Silurian species occur ; nearly all are such as are met with in Lower Devonian 
and in Upper Silurian rocks — Tentacidites, Orthis, Ctenodonta, Pileopsis (?) 
Sfrophoiuena, Bellerophon. South Africa and the Falkland Isles yield a similar 
fossil fauna. The Bilohites in this collection differ, some of them probably 
generically, from D'Orbigny's figured species. A little Bei/richia from the 
upper part of the Silurian series in Bolivia appears to be like a North Ameri- 
can form figured by Emmons as SQurian. 
December 5, 1S60. 
" On the Structure of the North-west Highlands, and the Belatious of the 
Gneiss, Red Sandstone, and Quartzite of Sutherland and Ross-shire." By 
Professor James Xicol, F.G.S. 
Geologists' Association. — This Society re-assembled for the winter Session 
on the 5th November, at 5, Cavendish Square, when the Rev. TTalter Mitchell 
gave a lecture "On the AppKcation of Crystalography to Mineralogy and 
Geology." 
Crystalography, it was stated, was capable not merely of explaining many 
facts comiected with mineralogy, but also of throwing light on various phe- 
nomena belonging to geology. Thus, with respect to the latter science, the 
cleavage of crystals illustrated the great cleavage planes of the stratified meta- 
morphic rocks, and their modified form assisted in determining the temperature 
at wliich strata had been produced. The views and researches of Mr. Clifton 
Sorby were dwelt upon, and the geometrical laws of Crystalography treated at 
some len2:th 
Dec. 3:iS60. 
Mr. IMitchener reaa a paper on a New Red Sandstone quarry at Stourton, in 
Cheshire. This quaiTy is remarkable for the abundance of reptilian footprints 
which it contains. 
Mr. Pickering presented to the Association a very fine collection of land- and 
fresh-water fossil sheUs from the Upper Tertiary deposits at Copford. in Essex, 
accompauyning his observations by an interesting paper descriptive of the 
localities wher^ they were obtained; and referring also to other brickfields and 
deposits at Fisherton, West Hackney. Reculvers,"and Kennet YaUey. 
