446 D. MACKINTOSH ON THE ERRATIC BLOCKS OF 
tion. But the 10-feet boulder at Wolverhampton and the small 
boulders near Wroxeter (probably Arenig) show that a few boulders 
at least may have been miscarried or dropped by the way. It is 
probable that more of these miscarried boulders may yet be dis- 
covered. Around the Clent and Lickey hills the boulders are found 
in a yaried deposit which I believe to be a representative of the 
Lower Boulder-clay of the north-western plain; and it is worthy of 
remark that in a clay-pit near Preesgweene (Chirk) a number of 
Arenig boulders may be seen lying on or near to the surface of a 
Lower Boulder-clay which is surmounted by a nearly stoneless upper 
or brick-clay (1878). A little consideration will render it probable 
that the Arenig dispersion did not all at once turn round in the 
neighbourhood of Welsh Frankton, and then make its way in a 
straight line to the Clent and Lickey hills, but that it probably 
curved round as shown in the map. By this time the cold must 
have increased so as push the “ cold wall” as far south as the above 
hills; for the positions of at least most of the boulders is such as to 
show that they could not have owed their downfall mainly to the 
circumstance of being intercepted by these hills. There are large 
boulders among the hills up to at least 900 feet (as lately ascer- 
tained for me by Mr. Amphlett, of Clent), but most of them occur on 
the south-west side of the range at lower levels*. 
V. CHALK-FiiInts AND Lirias Fossits assocIatTED with NorRTHERN 
BovuLpErs. 
Chalk-flints have been found by Mr. Aitken, F.G.S., and others 
high up on the Pennine hills ; but as they were more or less associated 
with worked flints of Neolithic age, there must always be some doubt 
about their having been transported by natural causes. I shall 
therefore confine attention to those which have been found imbedded 
in unmodified drift-deposits. In Boulder-clay, or in gravel, I have 
found them at Blackpool, Dawpool, Parkgate (numerous), summit of 
Halkin mountain (about 800 feet above the sea), around Wrexham 
and Ellesmere, in many parts of the peninsula of Wirral, near Run- 
corn, Delamere, Crewe, &c. Mr. Darbishire has found them near 
Leylands (Lancashire); Mr. Watts, F.G.S., at Piethorne, near Roch- 
dale; and Mr. Trimmer on the top of Moel-y-Tryfaen (Caernarvon) at 
a height of nearly 1400 feet above the sea. All these flints belong 
to the basin of the Irish Sea, and have almost certainly crossed the 
general course of the northern boulders on their way from Ireland. 
Gryphea incurva and a fragment of Lias have been found in drift 
near Chester (a specimen now in possession of Mr. Shone, F.G.S.), 
Gryphea incurva by Mr. Watts at  Piethorne, by the late Rey. Mr. 
Thornber at Blackpool, &. They may have come from Ireland or 
from the neighbourhood of Carlisle. I found a chalk-flint near 
Shrewsbury which may have come from Ireland or from Lincoln- 
* Should it yet be proved that the above boulders have found their way from 
West Central Wales by a route distinct from the one I have supposed, it would 
in no way interfere with the courses I have assigned to the northern-drift 
boulders, 
