18 FOSSIL INSECTS OF THE BRITISH COAL MEASURES. 



Order. PROTOBLATTOIDEA, Hancllirsch, emend. Pruvost. 

 Sub-order. Archiblattidse, Pruvost. 

 Family. Cacurgidae, Handl. 

 Sub order. Archimanticlse, Pruvost, 



Family. Cymenophlebidae, Pruvost. 

 Order. BLATTOIDEA, Haudlirscb. 



Family. Arcbimylacridse, Handl. 



Genera. Archimylacris, Asemoblatta, ManoUatia, Achnoblatta, Phyloblatta, Archxo- 



iiplie, Barroisiblatta, Grypoblatta, Mesitoblatta. 

 Familv. Mylacridse, Scd. 



Genera. Hemimylacris, Phylomylacris, Trilophomylacris, Soomylacris, Orthomylacris, 



Stenomylacris, and LitJiomylacris. 

 Family. Poroblattinidae, Handl. 

 Genus. Premnoblatta, Pruv. 



I have compared notes with M. Pruvost, and we have arrived independently 

 at the conclusion that for the present the classification of Handlirsch is, with few 

 emendations, the best to adopt, and most in keeping with the known facts. 



FAUNAL ASSOCIATION. 



Various collectors in British Coalfields have discovered not only insect-remains, 

 but a definite faunal association, of which the significance seems to have been 

 overlooked, and it has therefore not received the attention it deserves. 



Most of the insect-remains are found in ironstone nodules, and the beds in 

 which these nodules occur are usually light-coloured rocks more similar to hardened 

 clay than to normal shales. The nodules are in vast numbers, ranging in size from 

 half-an-inch to ten and twelve inches in diameter. The beds seem more com- 

 parable to the fireclays or seat-earths than to the ordinary fissile shales, and both 

 in lithological character and fossil contents stand in some measure apart from the 

 ordinary Coal Measure rocks. They are not restricted to one coalfield, but have a 

 wide distribution. Where a systematic search of beds of this character has been 

 made, the insect-remains have been found accompanied by a fauna in which 

 arthropods of a more primitive type than insects are conspicuous. 



The character of this fauna will be best understood by reference to the 

 following lists of fossils which have been recorded from certain localities : 



DURHAM COALFIELD. " Zone of Anthracomya jrfiillipsii (Will.) " in upper part 

 of the Middle Coal Measures ; Claxheugh escarpment, two miles west of Sunder- 

 land, Durham. 



PELECYPODA. j MEROSTOMATA. 



" Ancylus vinti, Kirkby " (ef. "Spat" of Belinurus trechmanni (Woodw.): 



Anthracomya pJiillipsii, Will.). DIPLOPODA. 



Anthracomya minima (Ludvig). A. Isevia, Euphoberia, sp. 



var. scotica. 



