286 Correspondence—Mr. Clement Reid and M. Verbeek. 
paleontologically similar, seem to be on different geological horizons ; 
as the first are associated with Keuper Marls, and the latter with 
Bunter Sandstones. G. Henry Kinanay, 
UPPER DEVONIAN IN DEVONSHIRE. 
Srr,—In connexion with Prof. Roemer’s paper in the April 
GronogtcaL Macazine, it may be of interest to remind geologists 
of the occurrence of the Clymenia limestone at Lower [unscombe, 
above the Goniatites intumescens stage. The highest bed the 
Professor appears to have observed at Lower Dunscombe was the 
flagey limestone with Goniatites. Want of time prevented my 
collecting from this part, and the short list in my paper is from the 
thicker-bedded limestone a few feet lower. In the field above, 
however, which, at the time I examined it, was newly ploughed, 
there was a quantity of shaly or nodular limestone, full of Clymenia 
(0. valida and C. striata).* 
This discovery of the Clymenia stage in South Devon is due 
to Mr. Etheridge, who determined the fossils. CLEMENT Rerp. 
DESCRIPTIONS OF THE FOSSILS FROM SUMATRA. ADDENDA ET 
CORRIGENDA. 
[See Guo. Mac. 1879, Decade II. Vol. VI. pages 385, 441, 492, and 535. ] 
I. The fossils, Nos. 1-4, pp. 386, 387, are from the Carboniferous Limestone of 
Sibelaboe, Highlands of Padang. 
11. Sparganilithes gemmatus, Pl. X. Fig. 4, is from the shale above the second coal- 
seam of Soengei-Doerian,? Highlands of Padang ; Eocene, 2nd stage. 
III.—The following twelve fossils are from the Limestone with Orbitoides and Corals 
at Batoe Mendjoeloe, Highlands of Padang ; Eocene, 4th stage, equivalent 
to stage y of Borneo :— 
Cardita, sp. Pl. X. Fig. 6. Cyprea subelongata. Pl. XII. Fig. 3. 
Lucina, sp. wy CADET te Cerithium, sp. An rs 
Pecten, sp as Reel 3 Turbo Borneensis ? a ath: 
Cidaris, Sp. 5 Pee : Phasianella Oweni 36 mG: 
Conus, sp. Pl XG Bigs Trochus, sp. 4a Ua 
Conus substriatellus. ,, pis Prenaster, sp. 8 
9 ”» hf 
TY. All the other sixty-five fossils are from the marls of the Island of Nias, probably 
’ of Miocene (late Miocene) age. 
V. The Cardita Sumatrensis, Pl. X. Fig. 5, is also from the Nias marls or clays, 
and not from the clay-bed associated with the coal of the 2nd stage, 
Eocene. 
R. D. M. Verperr. 
PROFESSOR MILNE ON VOLCANOS. 
Str,—When Professor Milne was writing his article on the dis- 
tribution of Volcanos I happened to say to him pretty much what 
is contained in Mr. Fisher’s letter in your last number. His answer 
was—“I wish to keep myself from committing the common error 
of many geologists who know a little mathematics, the error of 
imagining that I can create a mathematical theory for a phenomenon, 
when I am only acquainted with part of the cause of the phenomenon. 
On the supposition that rock is always of the same conductivity, we 
may find that an isothermal surface is probably one thousand feet 
1 Geox. Mace. Dec. II. Vol. IV. p. 454. 
2 See Guox. Mac. Dee. II. Vol. 11. p. 480. 
