It appears to be a common belief that there are two Old Red Sandstones in Scotland, and only two, which are referred to respectively as the Upper and the Lower. It is generally recognised that neither of these can be paralleled with any one of the subdivisions of the Devonian Rocks, properly so-called; though the fact that the Scottish rocks in question occupy a stratigraphical position somewhere between the top of the Silurian Rocks and the base of the Carboniferous System places their Devonian age beyond the possibility of a doubt. The Upper Old Red is considered by most persons to graduate upwards into the Carboniferous Rocks, which, by the way, is by no means universally the case. It is also stated, with equal confidence, and with as little regard to the facts, that the Lower Old Red Sandstone graduates downward into the Silurian Rocks, which it certainly does not, as will be shown more fully in another part of this paper. Furthermore, it is still commonly believed that bands yielding Silurian graptolites alternate with the base of the Lower Old Red Sandstone, and that Lower Carboniferous fossils occur in bands of rock interstratified with true Upper Old Red Sandstone. Both of these ideas are well known to have been due to errors of observation; yet the statements in question, having found their way into the papers set by examiners, seem destined to die a hard death, and therefore need to be contradicted.