Notices of Memoirs — Horizon of Dithyrocaris. 269 



Crag andLenham Beds in the Lower Pliocene group, bracketing them 

 as equivalent to the Diestian — but the " Box-stones " are scheduled 

 as Miocene. 



(In July will follow Mr. Newton' 's conclusions.) 



II. — The HoEizoisr of the Ttpe-specisiens of Dr. Scouler's 



DlTHYROGABIS TR1CORNIS AND D. TESTUDINEA. By PETER 



Macnair, F.R.S.E., F.G.S. 1 



Introduction. 



rnHE exact locality and as a consequence the precise geological 

 I horizon from which the type-specimens of Dithyrocaris tricornn 

 and B. testudineawere obtained has long been a matter of considerable 

 uncertainty. These type-specimens, now preserved in Kelvingrove 

 Museum, were first described by Dr. John Scouler in the Records of 

 General Science for the year 1835 (p. 137). The object of this paper 

 is to demonstrate that these fossils came from what was known as the 

 Gallowhill Quarries, and that they occupy a position near the top of 

 the Blackbyre Limestone of this district. 



Regarding the beds in which they were found Dr. Scouler says : 

 "This limestone is situated about a mile to the east of Paisley, and 

 ■was first pointed out to me by Mr. Murray, of the Glasgow Botanic 

 Gardens. This rock is distinct from and probably reposes on the true 

 Carboniferous Limestone, but as only a small patch of it is exposed, 

 the greater part being covered by the soil, it was impossible to 

 trace its relations -with the subjacent strata. This limestone is of an 

 extremely compact nature, with little plates of calcareous spar 

 disseminated through its substance. It readily splits into flags of 

 variable thickness, which are sometimes made of a multitude of 

 extremely thin layers, indicating that the whole stratum has been 

 formed by the gradual and tranquil deposition of transported matters. 

 The organic matters differ widely from those which we observe in the 

 Carboniferous Limestone. I could detect no Productidcs nor any 

 fragments of corals or stems of crinoid animals, nor, in short, any 

 decidedly massive production. Instead of these, on splitting up the 

 rock we observe impression of ferns of great variety and beauty, the 

 remains of entornostraca, which are of gigantic size when compared 

 with the analogous species which still abound in our lakes and pools. 

 Two species belonging to a new genus were obtained, and the 

 numbers might have been greatly increased had not the hardness of 

 the rock rendered the extraction of the specimens a difficult task." 

 It will be noted that though in the above account no definite locality 

 is mentioned, yet they are recorded as coming from a locality about 

 a mile to the east of Paisley. Another important feature of this 

 account is that it is such an exact description of the nature of the 

 limestone in which the fossils occur that we can have no hesitation in 

 identifying it with the bed to be described subsequently in this 

 paper. 



1 Reprinted in a slightly abridged form from the Transactions of the 

 Geological Society of Glasgow, vol. xvi, pt. i, 1915-17. 



