Marliles. 103 3d Clafs. Argillocalcites, penetrated vvlth bitumen, ful- phur, or pyrites. Bituminous Marlite. Bituminofer Mergel Schie fer of Werner. Colour greyifh or brownifh black. Fra&ure partly ftraight, partly curved, or undulatingly flaty ; the internal furfaces of the former rough, of the latter fmooth. The laminas either thick or thin. Fragments tabu’ar. Luflre of the ftraight flaty o, of the curved flaty 1,2. Tranfparencyo. Hardnefs 5. Spec. grav. from 2,361 to 2,442. Feels dry. Often contains copper pyrites. It effervefces with acids, even the lpe:cimens that have moft the appearance of coal, as thofe in Lefke, O. 1538, 1535. The fpecimen 1537 effervefces but weakly. 1t moft commonly bears impreffions of fifh or marine plants. It feems to be the Ihale bind of 4th Watfon, 344, yet its fpec. grav. according to him, is 2,68 t. This ftone muft not be confounded with bitu minous fliale (brand ichieferj, which it much re- fembles; that is an argillite, fcarcely effervefces with acids; this, a calcareous ftone, ftrongly ef fervefces with acids: its fpec. grav. at a medium l ift Family. 2,388. II 4 The