78 REPORT—1868. 
On a New Pterygotus, from the Lower Old Red Sandstone. 
By J. W. Satrm, A.L.S., F.GS., Se. 
The new species was obtained from the lowest Old Red, or Ledbury Shales 
formation. It is a very large one, and must have measured 7 feet in length when 
perfect. Its head very square; the base of the swimming-foot small in proportion 
to that of other species. The chelate antennz have the apices very greatly 
hooked, and the teeth close. Only fragments of the body-rings have been found. 
The tail-joint appears to have been oval. The specimens were found at Ewyas 
Harold, and are in the cabinet of Dr. M’Cullough. 
On the Relations between Extinct and Living Reptiles, and on the present state 
of our knowledge of Pterodactyle. By H. G. Srey, 
On the Classification of the Secondary Strata of England. By H. G. Seney, 
On a Remarkable Incrustation in Northamptonshire. 
By Samvrn Suarp, F.S.A., F.GS, 
In the section of a gravel-pit near Wold, about 14 miles N.N.E. of Northampton, 
had been exposed a mass of incrustation of carbonate of lime, the nucleus of which 
consisted of the water-plant Chara vulgaris. This mass was 10 feet in horizontal 
diameter as exposed in the section, and reached inwards about 4 feet from the 
plane of that sectioa, as first seen by the writer. Its thickness was about 2 feet to 
2 feet Ginches. Adoye the mass of incrustation was a layer of a kind of calcareous 
paste, of a thickness of from 6to 10 inches; and below it a similar layer of from 3 to 
Ginches. This paste consisted entirely of the crushed material of the incrustation, of 
which it contained many fragments. Atthe bottom was a mixture of gravel and 
soil, of the thickness of about 9 inches. 
The gravel in the pit is stratified. The strata ran up to the mass of incrustation 
on either side, sharply abutting upon it; and lower strata ran quite underneath, 
showing that there had been no partial subsidence or disturbance below. 
It was evident that there had been formerly a pool of water at this place—about 
10 feet across, and about 5 feet deep; the form of which, as shown by excavation, 
was basin-shaped, rounded at bottom, and spreading somewhat at top. 
The writer concluded from these facts that this pool had been artificially formed ; 
that the water had been highly charged wlth carbonate of lime; that, when the 
Chara came to grow init, it became inerusted ; that, by the process of the alternate 
or continuous growth and incrustation of the plant, the pool ultimately had been 
choked up, and becoming a mere quagmire, had finally been filled in with soil. 
The mixed gravel and soil at the bottom he thought had been the bottom of the 
pool; and the lower calcareous paste produced by pressure of the superincumbent 
weight, and the upper by the trampling of cattle in drinking. 
The pit is situated on the slope of a valley; the gravel is very open, and over- 
lies the porous beds of the ferruginous Northamptonshire sands; these repose upon 
the Upper Lias. No water had ever been known to, nor under existing conditions 
could possibly, stand in this gravel-pit. 
The writer, therefore, contended—as great alterations in the local conditions had 
taken place since the time when this pool was formed and water accumulated in 
it to such a depth as to allow the Chara growing luxwiantly to within a foot of 
the surface ; as those alterations probably involved an eleyation of the district and 
the excavation in whole or in part of the present valley; and as-the formation of 
the pool could only reasonably be accounted for by attributing it to human ageney— 
that we had here anot er item of evidence of the high antiquity of the human 
race, 
The Norwich Crags and their relation to the Mammaliferous Bed. 
By J. HK. Taynor. 
