ON THE ERRATIC BLOCKS OF ENGLAND, WALES, AND IRELAND. 341 
distant sources are to some extent intermixed; and this intermixture of 
streams or boulders has to be studied in connection with the physical 
geography of the country during the Glacial epoch. 
4. Local hills have formed no effective barrier to some part of the dis- 
tribution of boulders. In the Midlands, e.g., they are abundant at a level 
of 618 feet, and not unfrequently lie on the edges of the precipitous side 
of a hill. 
5. Some streams of boulder, however, have travelled under conditions 
imposed by the hills and valleys as they now exist. 
6. There are glaciated boulders of local origin intermixed with those 
not of local origin; but it would seem that where the northern erratics 
are numerous very few of these are intermixed. 
7. There is also a distinct distribution of boulders from local hills (as, 
e.g., from Rowley Regis). 
8. There are boulders at almost every level, and, it may be added, 
beds of boulders are sometimes separated from each other in section by 
clays and sands, occasional boulders occurring in the separating clays. 
9. A very considerable proportion of the largest boulders are upon the 
surface, or just beneath the surface ; how far clays and sands may have 
been washed away from them, however, is a question. 
10. There are notable differences in the shapes of the boulders. Many 
are angular and subangular; many have their edges much rounded off; 
others are rough and broken as though just torn from the parent rock. 
In some collections of boulders there are signs of considerable rolling and 
wearing as by water; in others signs of ice action are fresh and unworn. 
WARWICKSHIRE. 
Mr. W. Jerome Harrison, F.G.S., forwards a note on three boulders 
in South Warwickshire. In North Warwickshire the watershed 
which divides the rivers running to the HE. and W. coasts of England 
respectively forms the boundary line on the coast to the remarkable 
collection of Welsh and Lake District and Scotch rocks described in 
previous reports as occurring in the Midlands. Of boulder clays equiva- 
lent to those found in the district around Birmingham, Mr. Harrison has 
found no trace in S. Warwickshire. The surface deposits there are mainly 
a light quartzose gravel, the stones small, with occasional flints. Hrratics 
of any size are rare. 
The two Sherbourn Boulders.—Two and a half miles S. of the town of 
Warwick lies the village of Sherbourn, close to the right bank of the Avon. 
At the point where the village street joins the high road is a block of 
Millstone Grit. It measures 2 ft. 5 in. x 1 ft. 10 in. x1 ft. The second Sher- 
bourn boulder lies further up the village street, nearly opposite the 
school-house. This is a granite block, the felspar of a reddish colour. 
Its dimensions are 8 ft. 2 in. x2 ft. Gin. x1 ft. Yin. 
The Exhall Boulder:—The village of Exhall is 9 miles S.W. of Sher- 
bourn, and 5 miles due W. of Stratford-on-Avon. The boulder lies by 
the roadside at the east end of the village. It is a quartzose block, with 
green specks, possibly vein-quartz. It rests on the trias near the junction 
with the Rhewtic beds. The surface beds of this district appear to be 
thin gravel, composed of small quartzose pebbles (in which are found 
car ep ennai and worm-tracks), but with many angular pieces of 
chert flint. 
