TRANSACTIONS OF THE SECTIONS. 67 
Scotland, and the similar rocks of Glamorganshire and South Wales, might belong to 
the carboniferous system. 
He estimated the mean thickness of the true Oid Red Sandstone of the South of Ire- 
land at about 3000 feet, including 800 feet of yellow sandstone. 
The author then described an east and west section across Ireland from Blackstairs 
mountain in the county of Wexford to the extremity of the Dingle promontory in the 
county of Kerry, and afterwards entered into some details as to the structure of the 
Dingle district and that round Killarney and Glengariff. He referred more _parti- 
cularly to the great difficulty which arose from the fact that the red and green rocks (for 
which Mr, Jukes had proposed the term ‘Glengariff grits,’ a term which had his entire 
concurrence) were conformable to the Silurian rocks of the Dingle district, while the 
Old Red Sandstone reposed unconformably on both; on the other hand, in the coun- 
try south of Dingle Bay, it should be mentioned these same Glengariff grits passed 
insensibly up into the Old Red Sandstone; and no want of conformity could be found 
in any part of the series, from the Glengariff grits as far up as the coal-measures; 
and the author exhibited a north and south section through the Dingle promontory to 
the valley of Kenmare, illustrative of his views. He then pointed out the analogy 
between the Glengariff grits and the brownish-red grits of the three districts in the 
north of Ireland already alluded to, referring to numerous sections which he had for- 
merly prepared, 
The author thought, on the whole, from the occurrence of similar felstones and 
ashes in the Silurian rocks and the Glengariff grits, and the facts stated above, that 
there was a double probability in favour of those rocks being of Silurian rather than of 
Devonian age, or at all events that he was justified in the classification which he had 
made on his map, and in distinguishing these rocks by separate letters and colours. 
Notes from the Barbary Coast, with Fossils. 
By G. F. Hapersuon. (Communicated by Dr. GLADSTONE.) 
In this communication there were described the promontory of sandstone stretching 
into the Atlantic, on which the town of Mogador is built; two islands, likewise of 
sandstone, one of which contains a remarkable central depression ; the sand-hills, and 
the barren sandy plain, which extends some 20 miles by 5 or 6 inland; and the Iheb- 
el-Hadeed, or ‘‘ Mountains of the Iron,” a day’s journey to the north of Mogador, 
There is a universal tradition that the plain was once luxuriant with vegetation, but 
had been gradually covered with sand. This could not have been blown from any 
desert, as the plain is surrounded on all sides by fertile regions, except that open to 
the sea. That the land is sinking, is rendered probable by the very low position of 
the town of Mogador, of a palace built long since by one of the emperors of Morocco, 
and of a circular fort erected by the Portuguese on the shore and now in ruins, and 
especially by the fact that it was the custom of the Moors in former times to drive 
their cattle to feed on the larger island, by a path which is now covered at low tide 
by about 10 feet of water. 
About half a mile from the northern gate of Mogador is a sand-hill, in which Mr. 
Habershon had seen what appeared the stems, branches, and twigs of many trees, 
but all converted into sand and hollow. Dr. Gladstone, who had suggested the pro- 
priety of bringing over some of these fossils, described the specimens accompanying 
the paper as branching irregular tubes of carbonate of lime, on the outside of which 
sea-sand of a very heterogeneous character was cemented by crystals of the carbonate. 
These specimens varied from half an inch to five inches in diameter; and though he 
had formed several theories as to their origin and nature, not one of these seemed to 
meet every point of the case. The communication was further illustrated by speci- 
mens of sandstone from Mogador and the islands, minerals from the province of 
Soos, and ironstone and chert from the Iheb-el-Hadeed. 
On the Geology of Caldbeck Fells, and the Lower Sedimentary Rocks of 
Cumberland. By Professor Harkness, F.R.S. 
The district alluded to in this communication forms the northern portion of the 
mountainous area of the lake district of Cumberland. Caldbeck Fells, including their 
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