262 ME. s. s. BUCKMAT^ OK [vol. Ixxiii,. 



Domerian would fall in the upper part of the Marlstone. The 

 highest layer of Marlstone on the Dorset Coast — the serrata bed ^ 

 with Harpoceratoid ammonites, ^ may, on the principle of dissimilar 

 faunas, be expected to be of different date from the Transition Bed 

 of the Midlands with Tilfoniceras and peculiar Dactjloids — a bed 

 of lithic condition similar to decomposed Marlstone. Removal of 

 these two horizons to Whitbian would certainly make for greater 

 zoological uniformity, see p. 276. 



The following comparative table of Scottish and English 

 Domerian may be given. 



Table II. — Domerian Sequence. 



Dates. Strata. 



f ^ 



Hemerse. Raasay.i Yorkshiee.- Cheltenham I>f. Somerset.-* Dorset 



DiSTRicT.3 Coast. '^ 



1. spinatum X 3-11? C. S. Base of 



Junction Bed. 

 6. Icevis X (12-21)? 



5. gibbosa X 22-26 C. Margaritatus 



Bed + 

 4. a.Igovianum ... X 27-31 ■ Shell Bed + 



3. ■:■ canthoides ... 



2. Icscense (Strata about 



the 3 Tiers) ? 

 1. Jieldingi 



1 The Scalpa Sandstone. 



- The numerals refer to beds in ' Geol. Whitby ' op. cit. pp. 73, 74. 



3 The cdgovianum fauna is not known from the Cheltenham district ; but is 

 recorded by Wright from Oxfordshire — Chipping Norton. 



■1 Even the spinatum deposit is often missing. 



5 See Day, loc. cit. and S. S. Buckman, op. cit. p. 66. Intermediate beds cannot 

 be placed on present evidence. A much fuller faunal sequence than is here recorded 

 between spinatum and algovianuvi seems quite likel3'. 



[X Fauna present, position surmised. C, S., Beds in known sequence.] 



For a further illustration, see fig. A, p. 265, and for further details 

 the remarks on that page. 



IV. Chaemouthiax. 



Some small portion of the lower. part of the ScaljDa Sandstone 

 belongs to the Charmouthian ; but its main mass is made up of the 

 Pabba Shales, 600 feet thick in Raasay, 700 feet in Skye.^ They 

 are richly ammonitif erous, especially in the lower 400 feet or so 



1 '• Jurassic Strata ' Q. J. G. S. vol. Ixvi (1910) p. 65, bed i. 



^ The species figured by Wright, ' Monogr. Lias Amm.' (1884) pi. Ixxxi, 

 figs. 4-6 as ' Harpoceras radians. Upper Lias Shale, East Brent Knoll, Somer- 

 set ' bears a label in Dr. Wright's handwriting ' Down Cliffs, Charmouth,' 

 and is from the top bed of the Marlstone of the Dorset Coast. It well re- 

 presents the forms here alluded to : they require to be worked out and named. 

 There is perhaps some connexion with J.m. psexidoradians Reynes, ' Geol. PaL 

 Aveyron.' 1868, pi. i [his'], fig. 4. Wright's specimen is in the British 

 Museum (Natural History) No. C. 2200. 



^ These thicknesses were communicated to me by Dr. Lee. 



