130 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 8, 



shales which, they traverse could have remained open and been filled 

 from the water of the sea which deposited the overlying rocks, like 

 the Liassic veins in the Carboniferous limestone of the Mendips so 

 admirably described by Mr. C. Moore *, seems altogether incredible. 

 The explanation of the phenomenon which I would suggest is as 

 follows : — that at the time when the upheaval which produced the 

 fractures took place, the shales were already covered by beds of soft 

 and unconsolidated sand, and that, as the fissures gradually opened, 

 tbe sand as gradually found its way down into the interstices ; 

 finally the sand, both in the beds and the fissures, became consoli- 

 dated into a hard rock. 



§ 4. Summary of Observations and Conclusions as to the Relations of 

 the Palaeozoic and Mesozoic strata of the North-east of Scotland. 



From the details which I have now given, I believe that the 

 following propositions on the subject may be considered fully 

 established. 



(1) The Secondary rocks lie indifferently against all the members 

 of the Lower Palaeozoic series, from the Lower Silurian and associ- 

 ated granites up to the Upper Old Red Sandstone. 



(2) The Secondary strata which are thus in contact with the 

 Palaeozoic rocks are of very various ages, from the Trias to the 

 Upper Oolite inclusive, and contain representatives of all the sub- 

 divisions of the Jurassic series, except perhaps the Upper Lias. 



(3) There is a total absence in the Jurassic series of strata made 

 up of fragments of the rocks against which they repose ; and, on 

 the other hand, the conglomerates, which are by no means rare in 

 that series, are made up of fragments of rocks totally different from 

 these. 



(4) There are no indications whatever in this series of Secon- 

 dary strata that, as we approach the Palaeozoic rocks, we are coming 

 to an old shore-line. 



(5) The Secondary rocks exhibit signs of having undergone great 

 disturbance, being bent into numerous folds, broken up by many 

 faults, and traversed by fissures filled with materials from above ; 

 their fossils are also much more frequently distorted by pressure 

 than those of the equivalent strata in England. 



(6) The evidence of disturbance and dislocation in the Secondary 

 strata increases as we approach the Palaeozoic rocks, till at last the 

 beds of the former are often found in a completely crumpled and 

 crushed condition at the points of contact. 



All these facts point to one conclusion — namely, that the Secon- 

 dary strata of the north-east of Scotland owe their present positions 

 and their consequent remarkable preservation from the denudation 

 which has removed such enormous masses of contemporary deposits 

 in this area, to great faidts, which have thrown them down, pro- 

 bably several thousands of feet, below their original level. I find 

 that Prof. Geikie has already arrived at this conclusion with regard 



* Quart. Joum. Geol. Soc. toI. xxiii. (1867) pp. 483, 491, &e. 



