396 



MR. S. S. BUCKMAlSr ON 



[vol. Ixxviii, 



yield quite a rich harvest, and are well worthy of investigation. 

 Only in certain cases have I been able to attack the beds in 

 the cliffs, a ybyj laborious and unsatisfactory task, and therefore 

 my information is not so complete as it might be. But, with the 

 help of Day's section, it may be possible to work out the main 

 sequence — sufficiently, at any rate, for present purposes. 



Table I, below, gives in the two left-hand columns a summary 

 of Day's information, with my interpretation of his fossil names in 

 square brackets, and in the two right-hand columns are the details 

 which I have collected — the sequence and position in certain cases 

 being supposititious. •- 



Table I— Dombbian (fri^-sfinatusi) Deposits, Thoencombe Beacon. 



Day's Details. 

 Strata. Fauna. 



S. S. Buckman's Details. 



Brown sands 

 and sandstones. 



(Blocks of 

 indurated sand.) 



Margaritatus- 



Stone. 

 {Ma rga ritatus- 



Bed.) 



Grey and brown 

 sands witli 

 nodules. 



Ammonites. 



spina t us 

 [^Amaltheus 



armiger ?] 

 Ammonites 



bechei. 

 \_Anisoloboceras 



nautiliforme.j 



Ammonites 

 marga7'itatus. 



\_Amaltheus cf. 

 amaltheus 

 and other 

 species."] 



A.Jimhriatus. 



\_Lytoceras 

 Jimhriatum 

 Wright {non 

 Sowerby), Mon. 

 Lias Amm, 1883, 

 pis. Ixxi, lxxii = 

 L. postfimhria- 

 tum Prinz- 

 Vadasz.J 



' Masses of 

 Jlhynclionellce 

 of small size.' 



* In some places 

 lumps composed 

 chiefly of the 

 stems and arms 

 of Pentacrimis 

 johnsonii 

 Austin.' 



Strata. 

 Thorncombe Sands 

 with Tetrarhynchia- 

 thorncombiensis Bed. 

 (The ' RhyncJionella- 

 northamptonensis ' 

 Bed.) Compact 

 brown marly rock 

 with numerous 

 Rhynchonellids, 

 which weather out 

 cleanly. 

 Margaritatiis Bed : 

 Yellowish-brown, 

 blue-centred, marly 

 stone. 



Faun a. 

 Tetrarhyn cli ia 

 tho7^ncombiensis= 

 ' jRhyncJionella 

 northamptonensis ' 

 (auctt.) Walker in 

 Davidson. A thin 

 sharp-edged Zeil- 

 leria. 



Amaltheus spp., and 

 Lytoceratid, as 

 cited in col. 2. 



Down-Cliff Sands with 

 massive sandstone- 

 bed. Pale yellow 

 with blue centre. 

 Mainl}' unfossili- 

 ferous, but fossils 

 crowded in certain 

 small portions which 

 resist wave-action : 

 these supply the 

 fossiliferous pebbles. 

 The j^ellow pebbles 

 can be assigned to this 

 bed with fair cer- 

 tainty; but the blue 

 may be mistaken for 

 Starfish-Bed or for 

 Shell-Bed, or vice versa. 



Numerous small 

 Ithynchonell ce of 

 cuboidal form, with 

 sharp-cut ribs. Some 

 small Amaltheids in 

 the yellow stone. 

 Many small Amal- 

 theids in blue peb- 

 bles. Pebbles with 

 numerous fragments 

 of crinoids in a blue 

 sandstone perhaps 

 belong here. 



