Scientific Intelligence Geology. 405 



the following is a description : It presented 4 incisor teeth, 2 

 canine, 4 false molars, and 6 true molar teeth ; in all, 16 teeth 

 in a continuous series ; that is, tlie dentary formula of man, and 

 of some monkeys. . The incisors differ little from those of man. 

 They are a little more inclined anteriorly, thus resembling more 

 the arrangement in the monkey tribe. The canine teeth are 

 sharp and prominent, less so, however, than in most of the quad- 

 rumana. The first false molar tooth has only one strong tuber- 

 cle ; in man it has two. The second false molar has two tu- 

 bercles as in man. The three true molars are equally similar 

 to those in man except the last, which extends a little farther 

 from before backwards. These molars are, like those of man, 

 divided into four tubercles by two furrows, which cross at right 

 angles in the middle of the tooth. In their state of detrition, 

 one would believe that he was looking at the molars of a man of 

 forty years of age, reduced to about half their natural size. This 

 jaw, and the phalange which seems to belong to it, were found 

 at Sansan in a layer of marl, which is covered by a regular bed 

 of compact limestone, and they were mixed in a confused man- 

 ner with bones of various species of deer, of the Anoplotherium, 

 the Palseotherium, &c. Here, then, we have an example of a 

 mammiferous animal of the monkey tribe, which, judging from 

 the jaw, must have been .about three feet in height, contempo- 

 raneous with the Palaeotherium, Anoplotherium, and other ex- 

 tinct genera that have long been regarded as the oldest mammi- 

 ferous inhabitants of our continents. 



22. New Expression for determining the various circumstan- 

 ces connected with the Dip,$c. of Stratified Rocks. Dr Ander- 

 son of Perth communicates the following new expression, which 

 he has deduced for determining the various circumstances con- 

 nected with the dip, &c. of stratified rocks. Let A and B be 

 two stations, whose difference of level is denoted by h, positive 

 when B is above A, and negative when otherwise; and let d 

 represent the horizontal distance between them. Also let D de- 

 note the angle of the dip of the stratum observed at A ; I the 

 horizontal angle formed by the plane of the dip, and a vertical 

 plane passing through A and B ; and lastly, let E denote the 

 angle of elevation of B with respect to A, when that angle can 

 be measured by the two stations being visible from each other. 



VOL. XXIT. NO. XLIV. APRIL 1837. D d 



