286 Proceedings of the Royal Society of Edinburgh. [Sess. 
There is nothing in the structure or contents of the glauconite boulder 
of Belhelvie (A 9) which suggests its connection with the “gaize” of 
Moorseat, but there is no doubt that it is linked with and must have 
formed part of the strata from which the other boulders were derived. 
From the entire absence of calcareous matter, I conclude that it is not a 
fragment of the glauconite base of the true chalk, but a passage bed, similar 
in character and position to the glauconite base of the chalk of the west 
of Scotland (base of bed II of Professor Judd) or of Ireland. In view of 
the evidence pointing to the possibility that members of the Lower 
Cretaceous rocks occurred in the north-east of Scotland, it seems possible 
that it may represent the Upper Greensand or Chloritic Marl. Too much 
weight must not, however, be given to the lithological character of the 
deposit without the support of fossils ; the bed may be the homotaxical 
equivalent of chalk at a higher horizon : in any case it represents an early 
stage of Cretaceous submergence in the north. 
I saw no fragments of sandstone associated with the boulders at 
Belhelvie which might be referred to the estuarine deposits of the west, 
and therefore I infer that these beds did not occur in the locality from 
which these boulders were derived. But B I may represent an estuarine 
mud laid down at a distance from land, and the sponge beds and those 
containing much terrigenous material might be expected to follow as the 
natural sequence of events. 
Though one cannot say at present with what horizon in the English 
series the beds containing spongarian remains synchronise, they probably 
held a low stratigraphical position in the Scottish series. My reasons for 
thinking so are based on the remarks made by Dr Fraser Hume* on the 
relation of spongarian bands to the adjacent and subjacent strata in the 
Cretaceous series of Ireland. Dr Hume says, “ Such [spongarian] bands in 
many cases immediately overlie or are directly connected with beds dis- 
playing evidence of the commencement of depression, or partial elevation 
of deep-water beds accompanied by current action.” In support of this 
he cites the occurrence of sponges in the Plocoscyphia meandrina layer 
at the base of the Chalk Marl in the South of England, and the Chalk 
Rock of Devon, Eastbourne, and the Midlands as an instance of the re- 
appearance of spicules on the elevation of the sea-floor. “ In Antrim the 
abundance of these glauconite casts of spicules is noticeable as long as 
the limestones contain small fragments of quartz and other detrital 
minerals, but the sponges attain their maximum development (forming 
definite bands) at the point where detrital minerals become rare, and pure 
* “The Cretaceous Strata of County Antrim,” Q.J.G.S.^ vol. liii, 1897, p. 602. 
