REPORT OF MEETINGS FOR 1902 229 



(II.) The Siccar Point. 



First, as regards the facts. Standing on the bare rock 

 just at the foot of the cliff, and looking seaward, we see 

 before us a kind of rough gravel pavement, sloping gently 

 towards the sea. Here and theie the pavement has been 

 worn through bj the action of the sea and the weather, 

 and patches of rock of quite a different kind appear through 

 the openings thus made. These latter rocks are clearly quite 

 on edge, and it is equally clear that the "gravel" just 

 referred to li6s across the ends of these upturned rocks. 

 To determine the ages of the two recourse must be had to 

 a special mode of investigation, made use of by geologists. 

 This is based upon the principle that certain forms of life 

 lived at certain definite periods of the Earth's history, and 

 neither before those times nor after. In some cases, as in 

 the case of the three graptolites mentioned a few sentences 

 above, the evidence is very precise and exact, and is implicitly 

 trusted by geologists of all shades of opinion. If, therefore, 

 we desire to know the age of the oldest rocks seen beneath 

 the "gravel" at the Siccar Point we must search these rocks 

 for fossils, and see what can be learnt from them. This has 

 been done. I have myself got out one or two graptolites 

 of the species given in the foregoing lists as having been 

 obtained from Old Cambus quarry ; and other geologists have 

 done the same on many former occasions.* We may, therefore, 

 take it for granted that the older strata underlying the 

 "gravel" at the Siccar Point are really the Gala Eocks, 

 and are the equivalent in time of certain other rocks known 

 to occur elsewhere. 



This being the case, the next point to consider is whether 

 these particular Gala Rocks were ever covered by other strata. 

 A vast mass of evidence points to the conclusion that they 

 have been so covered. In the English Lake District the 

 thickness of the Silurian strata left there now — and the 

 highest beds have gone — above the same geological horizon 



* In these remarks I wish to make nse of evidence for which I 

 can myself vouch, rather than base what is said upon the work of 

 others. 



