_Saccammina_, 96 _Saccocaris_, 244 _Sagenodus_, 263 _Salterella_, 192 Sandstones, 71 _Sanidophyllum_, 115 _Sarcophilus_, 287, 295 _Sargus_, 272 _Scala_, 191, 198, 199, 200, 202 _Scalaetrochus_, 194 _Scaldicetus_, 297 _Scaphella_, 202 _Scaphites_, 209 SCAPHOPODA, 188 _Scenella_, 193 _Sceparnodon_, 289 _Schizaster_, 148 _Schizodus_, 175 _Schizophoria_, 162 _Schloenbachia_, 209 _Scutellina_, 146 Sea-beds far from the present coast, 29 Sea-bream, 272 " -cucumbers, 148 " -firs, 119, 122 " -mats, 154, 155 " -pen, 119 " -urchins, 59, 143 " characters of, 144 Sedentary worms, 154 _Seguenzia_, 199 _Selenaria_, 158 _Semele_, 185 _Semicassis_, 198 _Seminula_, 164 _Semionotus_, 262, 263 SEPIOIDEA, 205 _Serpula_, 154 Serpulite limestone, 74 _Sertularia_, 119, 122 Shales, 69 Sharks, 267, 269, 270, 271 Shell-limestone, 74 _Shumardia_, 227 _Sigsbeia_, 143 Siliceous rocks, 71 Silicified wood, 24 _Siliquaria_, 198 Silurian bivalves, 177 " brachiopods, 160 " brittle-stars, 142 " cephalopods, 206 " cirripedes, 241 " conodonts, 153 " corals, 113 " crinoids, 135 " Foraminifera, 96 " gasteropods, 193 " graptolites, Victoria, 128 " Hexacoralla, 114 " Octocoralla, 115 " Ostracoda, 235 " palaeechinoids, 144 " Phyllocarida, 246 " plants, 82 " Radiolaria, 102 " sponges, 109 " starfishes, 140 " stromatoporoids, 121 " trilobites, 228 _Siphonalia_, 198 _Siphonia_, 110 _Siphonotreta_, 160 SIRENIA, 298 _Sistrum_, 202 Slate, 70 Smith, William, 26 Smittia, 158 _Solarium_, 198 _Solenocurtus_, 187 _Soletellina_, 188 Sphaerosiderite, 80 _Sphenopteris_, 85, 89 _Sphenotrochus_, 118, 119 _Sphenotus_, 177, 179 _Sphyrna_, 270 _Spirifer_, 160, 161, 162, 163, 164 _Spiriferina_, 165 " -beds, 208 _Spirillina_, 96 _Spirorbis_, 154 _Spirula_, 205 _Spirulirostra_, 205, 210 _Spisula_, 188 _Spondylostrobus_, 91 _Spondylus_, 175, 184, 185 SPONGES, characteristics of, 64, 107 _Spongilla_, 72 _Spongodiscus_, 103 _Spongophyllum_, 116 Spoonbill, 283 Spore coal, 76 _Squalodon_, 295 _Stacheia_, 97 Star-corals, 119 Starfishes, characters of, 61, 139 _Staurolonche_, 103 _Stauroneis_, 92 Steno, 25 _Stenopora_, 117 _Stenotheca_, 192 _Stephanella_, 109 _Stephanograptus_, 126 _Stephanotrochus_, 118 _Sthenurus_, 290 Sting-ray, 271 _Stomatopora_, 158 Storing fossils, 320 Stork, 283 Strata, superposition of, 41 " vertically arranged, 44 Stratigraphical series, general thickness, 44 Stratigraphy, 27 _Strepsodus_, 261 _Streptelasma_, 113 _Stricklandinia_, 160 _Stromatopora_, 120, 121 _Stromatoporella_, 121, 122 STROMATOPOROIDS, 63, 120 _Strombus_, 184, 204