ROCKS OF PEMBROKESHIRE. 
There is no evidence whatever of an intrusive 
junction; and I cannot make out how any one 
conversant with the usual conditions in districts 
where the old rocks are much broken could so 
mistake so clear a case of faulted junction as to 
believe that it was one of eating through the 
sediments, as shown in his section, by a great 
granite mass. The sketch, fig. 7, shows the 
actual conditions seen here, and the nature of 
the junction. Higher up the hill on this side 
Cambrian conglomerates are seen in contact with 
the Dimetian, so there is much crushing and con- 
fusion of the rocks on this as on the opposite 
site. KEverything points unmistakably to results 
due here entirely to faults. The sketch itself is 
sufficiently clear on this point. Another quarry 
is referred to by Dr. Geikie as showing intrusive 
junction higher up the valley on the road to 
Rhoscribed. This is given in sketch fig. 8, 
which [ think is almost sufficiently clear without 
description. It shows the Cambrian beds, as 
usual, thrown towards the older rocks, the Di- 
metian, by a fault. Here again there is not the 
slightest change produced in the material com- 
posing the Cambrian rocks, but much crushing js 
visible in those at the junction, with evidences of 
infiltration along joints. 
In Dr. Geikie’s map, at this point and towards 
Rhoscribed, a far wider space is shown between 
the dissevered Dimetian masses than really occurs, 
as the Dimetian can be clearly seen crossing the 
road at a distance only of about 35 yards from 
the other mass. Between these two masses the 
Cambrian rocks are dropped in, in a folded con- 
dition, dipping away from one and towards the 
other. The section, fig. 9, explains fully the 
manner in which the Cambrian beds have been 
dropped in among the Dimetian rocks to the 
west of Porth-clais. By failing to recognize the 
effects of faults in this area, the Director-General 
has been led into many serious errors, even in 
mapping the Cambrian rocks. To some series he 
has given an undue thickness, and others he has 
placed where they do not occur. At first sight a 
confusion of the beds might be made; but if one is 
at all acquainted with the order of succession of 
the rocks in this area and the peculiarities recogniz- 
able at various horizons, the whole matter becomes 
at once clear. As shown in the section at Porth- 
clais, the lower beds, 2 and 3, have been several 
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