285 
1914-15.] Chalk Boulders from Aberdeen, etc. 
The fine-grained sandstone, or gaize, of Moorseat contains fossils which 
are referred by Mr Jukes-Browne ^ to a ‘'Lower Cretaceous rock, but high 
in that series, corresponding approximately to the Aptien stage in France, 
and to the Lower Greensand or Vectian in the Isle of Wight.” Though in 
neither case have these rocks been proved to be in situ, their occurrence 
is evidence that members of the Lower Cretaceous series have at one time 
covered part of the north-east of Scotland. 
There is yet another source which affords evidence of the occurrence 
of Cretaceous rocks in Scotland, viz. the flints which are scattered broad- 
cast on the surface of a large area in Aberdeenshire and the neighbour- 
ing counties. Dr Gibb kindly sent me a series of these collected in the 
neighbourhood of Cruden, all of which contained casts of Cretaceous 
fossils. These have been examined by Mr Jukes-Browne, who sends me 
the list appended to this paper. Most of them are Upper Chalk forms, 
but the fact that Inoceramus mytiloides occurs amongst them strengthens 
the argument below that Middle Chalk may be represented. Thirteen 
thin sections were cut from these flints to see if any comparison could be 
made of the chalk in which they were formed and that of the Belhelvie 
boulders. Examination showed that all were pseudomorphs of calcareous 
oozes in which varying proportions of Foraminifera, spheres, and shell 
fragments were the chief ingredients. Though all contained sponge 
spicules, they were not exceptionally numerous, and there was no evidence 
that the chalk contained colloid silica in globular form ; it may therefore be 
inferred that none of the flints originated in a sponge bed. No mineral 
grains were detected in any of the sections, nor were any Kadiolaria seen. 
The boulders from Belhelvie may, I think, be taken as evidence of the 
upward continuation of the Upper Cretaceous series in the north-east of 
Scotland. 
Although no fossils have been found in them, the study of the micro- 
organisms as well as the larger particles of calcareous debris which they 
contain leaves no doubt that, wdth exception of the two first, they are 
fragments of the uppermost member of the Cretaceous series, viz. the 
Chalk. Taken collectively, they show a gradual passage from what is 
practically a Greensand, consisting entirely of terrigenous material and 
glauconite, to a pure calcareous ooze. 
In the twenty-two examined, no two are alike either when viewed as 
thin sections, or when they are chemically analysed, or when the pro- 
portional numbers of the various component organisms are compared ; 
consequently they must represent a very considerable thickness of chalk. 
* Geological Magazine, Dec. 4, vol. v, 1898, p. 32. 
