TRANSACTIONS OF THE SECTIONS. 69 
ft. in. 
Length of femur ..scc.csceseterecccsccasesesesservaccean, 110 
Breadth of femur at distal extremity ...sceceeeeesseeeeeeee 0 105 
Length of tibia... .. ccc ee eee RC: COC Omm nit sjererees ba OraRO 
Breadth of tibia........ eR Galshelatatsls fame ZR arya <cafs ferchays; 4 spurl aD 
Length of fibula ..........00005 Sarath sits esaegatona nels eror Seer 0 6 
Breadth of fibula at femoral end ....5..sceeeeeeeeeeeeereee OF G6 
The proportion of the head to the neck, measuring from the point of the superior 
maxillary to the extremity of the angular piece of the lower jaw, is as 5 to 8, the 
head being, therefore, rather more than half the length of the neck ; its proportion 
to the whole skeleton is about 1 to 6. This large proportionate size of the head 
corresponds very nearly with that of P. megacephalus, Stutchbury, and an unde- 
scribed species from Redcar, in the Museum of the Yorkshire Philosophical Society, 
named P. Zetlandicus by Professor Phillips, from both of which it differs in several 
very important particulars. 
Note.—Since reading the above paper, the authors have received information, 
through the kindness of Mr. Martin Simpson, the Curator, respecting a Plesiosaurus 
in the Whitby Museum, which in its proportional measurements appears to ap- 
proximate very closely with the above species. 
On an Extinct Volcano in Upper Burmah. By W.T. Brayrorn, F.GS. 
The most conspicuous object visible from the River Irawaddi, between its mouth 
and the capital of the kingdom of Ava, is the lofty hill of Puppa, which lies about 
100 miles haytnd the British frontiers, on the east or left bank of the river, and 
about 35 miles E.S.E. of the town of Pagau, famous for the enormous number and 
the magnificent architecture of its ancient Buddhist temples. The whole undulating 
plain between the River Irawaddi and Puppa Hill consists of the Upper Tertiary 
sands. The hill itself is a fine extinct volcano, its height probably a little under 
5000 feet. The upper part of the cone is free from the’ forest which covers the lower 
portion, and acomplete change in the flora and the presence of some plants common 
to temperate climates show the effect of the altitude reached. The upper part of 
the cone is solely composed of ash-beds ; towards the base there is an abundance of 
old lava-flows, and a thin cap of these has protected a portion of the soft under- 
lying sands, so that the hill is surrounded by a broad terrace, the edges of which 
rise abruptly 300 or 400 feet from the country around. Some small, flat-capped 
hills, detached from the mass, present a peculiar appearance, from their cap of black 
ash-beds and lava.contrasting with the white sand of which they are principally 
composed. 
The following section was obtained from an examination of the cliff surrounding 
the terrace (all the beds horizontal) :— 
1. Laya-flow, forming a cap of variable thickness. 
2. Soft white sand, somewhat micaceous, about 80 feet. 
3. (Very local) bed of pumice, 5 feet. 
4, Volcanic ash. and scorie, with rounded quartz-pebbles, varying in thickness 
from 5 to 20 feet. 
5. Ferruginous conglomerate, containing the iron-ore of the country, thin. 
6. Soft, coarse, yellowish sand, containing pebbles, about 100 feet seen. 
The author believed that the sands above and below the ash-hed No. 4 were 
identical with those containing fossil wood and bones in various bartg of the Iva- 
waddi valley. He concluded that the commencement at least of the volcanic out- 
burst of Puppa was synchronous with the existence of Mastodon latidens and the 
several Pachydermata and Ruminantia, remains of which have been collected at Ge- 
nanthamug and other places in Upper Burmah. These beds contain several fossils 
identical with those of the Sewalik beds of India, which have commonly been 
considered as Miocene. The large proportion of bones of Ruminants (Oxen and 
Deer) in the Irawaddi beds may perhaps suggest a somewhat more recent epoch. 
The shape of the volcanic cone is well preserved, with the exception of the crater 
being broken down on one side, so that no lake exists within. ‘The climate, how- 
ever, of this portion of Burmah is extremely dry, and the action of subaérial denuda- 
