Sullivan & O'Reilly— On Dolomite Bed of JYorth of Spain. 231 
can we affirm that all the limestone of the summits in the said eastern 
region are exclusively carboniferous, it being quite possible that some 
of those many limestone sierras correspond, as indicated by Don 
: Paillette with regard to Pena Mellera, to rocks over the carboniferous 
formation in which they are disseminated." 
We have, unfortunately, no knowledge of Don Paillette's memoir 
I beyond the notice of his opinion given here, and cannot therefore say 
how far his opinion directly accords with ours as to the general 
question of the Jurassic character of the rocks of Eastern Asturias, or 
may have reference merely to the age of some local groups of beds. 
I In conclusion we hope that it will not be considered out of place 
if we express our satisfaction that the views which we put forward 
in 1863 regarding the geology of Santander, and which at the time 
were so opposed to much of the current opinions of geologists, turn 
out to be so much in harmony with all the results of subsequent 
investigations of the Hispano-Alpine Jurassic rocks as to require no 
substantial modification. We trust that we shall soon have an oppor- 
tunity of more thoroughly examining the region of the river Deva, 
the key of the geology of the whole of the Cantabrian chain, and of 
laying the results before the Academy. 
DESCEIPTIO^^^ OE PLATE XYIII. 
Illustrating Messes. Sfllivaist and O'Reilly's Faper — On the Great 
Dolomite Bed of the North of Spain. 
N. S. section of beds between the sea and the Valley of Udias, passing through the 
Valley of Comillas ; twenty-three miles west of Santander ; length of section, 
about four miles. 
Bed No. 1. . Greenish, and in some points slightly micaceous grey sandstone ; 
very soft, and yielding ; contains in places pieces of amber, 
and also traces of fossil plants, apparently marine, very soft 
and yielding. 
,, J^o. 2. . . Beds of shaly pyritic clays, with thin ripple-marked sandstone 
plates. 
No. 3. . . Hard shelly limestone. 
,, No. 4. . . Beds of clay containing dark grey nodules. 
,, No. 5. . . Thick bed of rather friable greenish sandstone, presenting no traces 
of fossils, and comparatively easily acted on by atmospheric in- 
fluences. 
No. 6. . . Thin beds of marly clay, containing nodular limestone, and 
abounding in fossils (oysters, trigonias, &c.). 
„ No. 7. . . Limestone beds of dark grey colour, the planes of stratification 
being generally marked by thin layers of black marly clay, 
and containing OrbitoUna concava, Lam., Rhynconella dcpressa, 
d'Ord., and Terebratula menardi. Lam. This would represent 
the lowest bed of the cretaceous formation immediately over- 
lying the dolomite. 
