234 Reports and Proceedings— 
with some scattered coprolitic pebbles, caps the lateralis-beds, and 
this band constituted the ‘Coprolite-bed ” of Leckenby. 
The thickness of the clays above the coprolites has been over- 
estimated ; it is probably not more than 300 feet. 
The ranges which have been assigned to some of the characteristic 
fossils, especially Ammonites Astierianus, Amm. speetonensis, and 
Toxaster complanatus, need to be revised and altered. 
The term “ Middle Neocomian,” as applied in the Speeton section, 
is unnecessary and misleading, seeing that a ‘Lower Neocomian ” 
fauna occurs both above and below the beds with Middle Neocomian 
types ; and, as stated by Meyer, marly shales exist between the Red 
Chalk and the Neocomian clays, strongly suggestive of a passage 
from the one to the other, and these beds contain many Gault forms. 
Thus there is probably at Speeton a continuous series of clays from 
the Jurassic to the Upper Cretaceous, and the deposition of these 
beds appears to have gone on contemporaneously with the erosion of 
the beds inland. 
2. “Notes on the Geology of Madagascar.” By the Rev. R. 
Baron. Communicated by the Director-General of the Geological 
Survey. With an Appendix on some Fossils from Madagascar, by 
R. Bullen Newton, Esq., F.G.S. 
The central highlands of Madagascar consist of gneiss and other 
crystalline rocks, the general strike of which is parallel with the 
main axis of the island, and also, roughly, with that of the crystal- 
line rocks of the mainland. The gneiss 1s frequently hornblendic ; 
its orthoclase is often pink; triclinic felspar also occurs in places; 
biotite is the most common mica, but muscovite is not uncommon ; 
magnetite is generally present, often in considerable quantities. 
The gneiss is often decayed to great depths, forming a red soil, and 
the loosened rock is deeply eaten into by streams. The harder 
masses of gneiss, having resisted decay, stand out in blocks, and 
have been mistaken for travelled boulders of glacial origin. Other 
more or less crystalline rocks are mica-schists, chlorite-schists, 
crystalline limestone, quartzite (with which graphite is often asso- 
ciated), and clay-slate. 
Bosses of intrusive granite rise through the gneiss. That east 
of the capital contains porphyritic crystals of felspar which near the 
northern edge of the granite are arranged roughly in a linear direc- 
tion; here also the granite contains angular fragments of gneiss. 
For the most part the granite of Madagascar is clearly intrusive, 
but this may not always be the case. 
The volcanic rocks are of much interest. The highest mountains, 
those lying to the S.W. of the capital, consist in their higher parts, 
of a mass of lava, for the most part basaltic, but with some sanidine- 
trachyte. The lava-streams are sometimes 25 miles long, and suc- 
cessive flows, up to 500 feet in thickness, are exposed by the valleys, 
From the great denudation which this area has undergone, and from 
the fact that no cones now remain, we may assume that this volcanic 
series is of some antiquity. Of the newer volcanic series there are 
numerous very perfect cones, dotting the surface of the gneiss in 
