220 J. T. Young — Freshwater Sponge in the Purheck Limestone. 



George's encounter with the Dragon, canter over the sandy beach of 

 St. George's Bay, and stumble on the remains of an old Koman road 

 which cut through a cave, leaving exposed to this day a breccia of 

 bone, flint flakes, etc. In specimens of this, submitted to Dr. Fraas, 

 he has recognized Bos priscus, superior and inferior molar, BMnoceros 

 tichorhinus, inferior molar. We pass around the Dog Eiver Pro- 

 montory under the celebrated stone-cut inscriptions, ford Dog Eiver, 

 cross the next point, and reach Juneh Bay in an easy three hours 

 from Beirut. About two-thirds the distance across the beach of this 

 bay we strike up the steep hill-side toward the apparently vertical 

 strata before us in the mountain. A short climb brings us to the 

 convent, under the very walls of which, and in a fig orchard, 

 outcrops the stratum of white chalky limestone whence so many 

 beautiful specimens have been obtained. The place is about 300 

 feet above the level of the sea, and a little more than a mile distant 

 from the shore. The exposed stratum is steeply inclined, as are all 

 the strata in that part, and the exposed rock abounds in specimens, 

 which lie in all directions, some of the fish passing through an inch 

 or more of thickness, i.e. the head deeper in the rock than the tail, 

 or vice versa. The rock is soft chalky white, easily cut or sawed, 

 and differs entirely from the Hakel rock, which is heavy, and brittle, 

 with a much more distinct tendency to split into layers than the 

 Sahel Alma limestone. 



But I have already exceeded the limits which I intended to assign 

 to this introductory article. The lithological and geological questions 

 which must be answered, the relation of the fauna of the two 

 principal localities, and the description of new and interesting 

 species, must be left to future articles. 



VII. — On the Oocurrenok of a Fkeshwater Sponge in the 



PuRBECK Limestone. 



By John T. Young, F.G.S. 



IN the course of a re-investigation into the vexed question of the 

 origin and nature of Chalk flints, the very natural suggestion 

 occurred to me that the remains of a freshwater sponge might 

 probably be found in the " flints " ' of the Purbeck limestones, and 

 a recent visit to Lulworth afforded the opportunity of verifying the 

 conjecture. Patches of spicules with valves of Ct/pris, etc., etc., occur 

 in most of the specimens then obtained. The spicules are fusiform, 

 slightly curved and tuberculated like those of Spongilla fluviatilis, 

 but larger. The longest spicule I have been able to measure is 

 about eir of an inch in length ; largest diameter yi-o of an inch. 

 The spicules of S. fluviatilis from Henley-on-Thames average from 

 To-T to To XT inch in length, and are about laVir inch in diameter. 

 The sketch Fig. h represents a small portion of a section of " flint " 

 (from Stare Cove) as seen by reflected light under a 2 -inch objective. 

 It has been touched with fluoric acid to bring out the spicules. 

 Before this was done, they were so obscure as to be scarcely visible, 

 although they are shown plainly enough on the weathered surface. 

 The specimen from which the section was cut is almost entirely 

 1 Or more properly " chert." 



