GEOLOGY. 279 



The purpose of the lecture was to give an explanation of the in- 

 terest attaching to two casts upon the table, the one that of a 

 skull, discovered and described by Professor Schmerling, from the 

 cave of Engis, in Belgium ; the other, discovered by Dr. Fuhlortt, 

 and described by Professor Schaffhausen, from a cave in Neanderthal, 

 near Diisseldorf, the former being the oldest skull whose age is 

 geologically definable, the latter the most aberrant and degraded of 

 human skulls. 



The nature and extent of the cranial modifications exhibited by 

 the man-like apes and by man were discussed ; and their modifica- 

 tions were shown to depend upon variation in the capacity and in 

 the form of the cranium, and in the greater or less development of its 

 ridges, and in the size and form of the face. The skull of a negro was 

 shown. Its breadth was small in proportion to its length, in 

 fact, was only six-tenths of it. The skull of a Turk, on the con- 

 trary, was in breadth nine-tenths of its length. All skulls come 

 under one or other of these classes. Taking eight-tenths of the 

 length as a standard from which to classify skulls according to the 

 proportion between their length and breadth, all that have for 

 breadth a less proportion than eight-tenths of the length are termed 

 dolichocephalic, or long-headed ; all that have a greater proportion, 

 or even that proportion (eight-tenths) of the length in the breadth, 

 are termed brachy cephalic, or round-headed. 



Skulls which are of the second class generally have the jaws 

 orthognathous, nearly or quite in a perpendicular line with the 

 forehead. Those of the first class have the jaws prognathous, or 

 more prominent than the forehead. 



If a line be drawn on a map from the centre of Russian Tartary 

 to the Bight of Benin, it will be found that north and east of this 

 line the heads are of the brachycephalic type ; south and west of it 

 they are dolichocephalic ; north and east the faces are orthogna- 

 thous ; south and west, prognathous. This, however, is a very broad 

 statement of fact. Near these points may be found heads of all vari- 

 eties of breadth ; but, as a rule, the round-headed races, Mongols, 

 Tartars, Turks (modified Tartars), are north of this line, and long- 

 headed. Negro races are south and west of it. 



These great changes are doubtless influenced by, and may be in 

 great measure caused by, difference of physical condition. So great 

 are the differences, that these points may be called the ethnological 

 poles. At the northern end are cold, barren, treeless plains ; at the 

 southern, the warm, rank fertility of the tropics. As we go away 

 from these ethnological poles, we find, in going from Tartary, the 

 Chinese become longer-headed and more prognathous ; the Green- 

 landers are long-headed ; so are the Esquimaux ; so are the North 

 American Indians. In fact, all heads vary as we depart from the 

 ethnological poles. 



A line drawn from the British Isles, through Europe and Western 

 Asia, to Hindostan, represents the Ethnological Equator, along which 

 the skulls are found to be oval. 



The question arises, whether the same varieties of the human race 

 have always inhabited the regions of the earth in which they are now 

 found. In Asia, in Africa, all remains that are found are of 



