<) FOSS1I, 1XSKCTS OF TITF BRITISH COAI- MEASURES. 



valuable information is supplied liy the deposits, or by the nature of the associated 

 forms of life. 



The great group of the Palseodictyoptera and certain of the Protorthoptera 

 and I'rotodonata had large wind's, and were powerful fliers. \Ve slionld therefore 

 expect to find their remains widely dispersed in deposits of varied nature. This 

 seems to lie the case. Compact heavy-bodied insects like the Hlattoids would have 

 a more limited range, and their bodies after death could not be carried to threat 

 distances. Larval forms would in most cases be included in the deposits in the 

 immediate neighbourhood of the area in which thev lived. 



]\I. Henri Fayol, in his description of the Coal Measures of Commeiitry, 

 France, shows that these deposits were laid down in narrow land-locked lakes of a 

 trough-like form lying in depressions of older schistose and crystalline rocks. 

 The trampiil waters received only the finest mud in suspension, and the resultant 

 mudstones have yielded a large insect-fauna, in which Blattoids are most numerous. 

 The bodies of the insects are preserved in many cases. Certain of the insects were 

 strong fliers, and their occurrence with the bodies intact indicates that they, in 

 all probability, haunted the vicinilv of the lakes and flew over them. When 

 strongly-flying insects like BoUotiites radstockensis or Lithosialis bronrjniarti died 

 upon the land, the wings, because of their membranous and cliitinous nature, 

 would persist after the destruction of the softer body, and be swept off into streams 

 after heavy rains or Hooding of the land-surface, their great superficial area 

 combined with their lightness making flotation easy. 



The transference of insect- wings from the land into water would be accom- 

 panied bv the drifting of plant-material, and the two would be buried together in 

 the deposit then formini;'. The wmt;' of Boltonites from Radstock was found with 

 plant-remains in deposits of this sort, and may be taken as a prool. supported as 

 it is by other examples of IVotodonate wings, that these insects lived over the 

 land and died upon it. 



The Palseodictyoptera, with their wings capable only of an up-and-down move- 

 ment in one plane at right-angles to the bodv, and, when in a position ol rest, 

 disposed straight outwards, are not likelv to have Frequented the ground, except 

 in the open. These insects, like ino>( of the I'aheo/.oie forms, were all ot large si/.e, 

 as contrasted with living tvpes. Pruvos! assumes that the characters of the wing 

 unfitted these insects fora fore>t life, and that they muM have been restricted to 

 flight in the open neighbourhood of swamp pools. I do not wholly ai^ree \\iih 

 this assumption, for the branches and leaves of the Coal Measure plants do not 

 seem to have had so great a densit v and interlacing of Foliage as seriously to 

 impede the flight of powerful \\mgeil insects. There seems no reason why these 

 insects should not Irive lived among the brakes of 1 .epidodend roid and ('alanntean 

 tree-, and after death fallen or been blown into adjacent waters. The lad that 

 isolated wings are often found in perfed condition and without any signs of wear 



