OREN 
186 PROF. BONNEY ON THE RELATION OF BRECCIAS [May 1902, 
summary *) is sometimes 100 feet thick, and the upper 150 feet.. 
But a diagram drawn by Mr. Goodchild? shows that there may be 
more than two beds: the solid Brockram-mass at Kirkby Stephen 
tailing off wedge-fashion as it approaches Appleby. The lower 
bed is strongly jointed, forming bold mural escarpments, and 
often supplying a good building-stone. The fragments are usually 
crowded confusedly together in regard to size, though their longer 
axes tend to he parallel with the bedding-planes. Those about 
2 inches in diameter dominate, but they run down to mere grains 
on the oneside and occasionally up to blocks 2 or 3 feet in diameter 
on the other ; being either angular or but little rounded. As a rule 
from 85 to 90 per cent. are Carboniferous Limestone, the remainder 
being sandstone from the same system,*® with a little chert, and 
shale. A few rounded pebbles of liver-coloured quartzite have 
probably been derived from some older conglomerate. A red sand-. 
stone occasionally forms subordinate bands in the Brockram, and 
the middle mass of that rock is strongly false-bedded. The frag- 
ments are hardly ever striated, but in one case the discoverers were: 
satisfied that the marks were due to ice-action. The materials in 
the Dumfries breccia represent the rock of that district.* These. 
Brockrams have evidently formed a marginal fringe to a rocky or 
mountainous region. Mr. Goodchild, who considers the ordinary 
Penrith Sandstone to be a desert-formation, suggests that the 
Brockrams were transported by shore-ice and deposited in water.’ 
If so, the drift must have been (roughly) north-westerly in the one 
district and south-westerly in the other, the sand being indicative of 
winds blowing more directly from the east. 
Ill. Tor ArmaAcu Brececras. 
Beds closely resembling these Brockrams, according to Prof. Hull,’ 
occur in the Permian of Armagh. The sections described exhibit. 
in the lower part a bed of breccia, 10 or 12 feet thick, composed 
(as I infer) of more or less angular fragments, embedded in a 
reddish sandy matrix, which passes locally into sandstone. The 
upper surface of this sometimes is eroded; at others the mass. 
graduates into a stratified conglomerate and boulder-bed, the blocks 
being from 18 inches to 2 feet in diameter. These vary from. 
angular to rounded, consisting of grit, felspathic sandstone, vein- 
quartz, and occasionally of limestone. Prof. Hull says that the 
boulders of grit (Silurian and Old Red Sandstone) must have 
travelled from 20 to 30 miles, and he attributes a glacial origin to 
the deposit. 
1 «Geology of England & Wales’ 2nd ed. (1887) p. 212. The thicknesses. 
given in Harkness’s paper, Quart. Journ. Geol. Soc. vol. xviii (1862) p. 206, are 
considerably less. 2 Geol. Mag. 1882, p. 2258. 
3 In one locality the bulk of the fragments consist of this sandstone. 
* The ‘ Crabrock’ of the Barrow district probably is.a kind of brockram, and 
a thin bed of breccia forms the base of the Permians near Whitehaven. 
> Trans. Cumberl. & Westmorl. Assoc. vol. ix (1885) pp. 46-47. 
® Quart. Journ. Geol. Soc. vol. xxix (1873) p. 402. 
