The Franciscan series extends with various interruptions for about six hundred miles along the Coast Ranges of California and Oregon and in it and its associated eruptives are found a very great number of occurrences of vein deposits that lie among similar surroundings, and a comparison of these with the deposit now under consideration yields some general analogies along with the striking differences.

Very often in traversing the serpentine areas, so frequently associated with the Franciscan, we come across included masses of partly recrystallized basic rocks or irregular areas or lenses of glaucophane, hornblende, or other basic schists. These are often cut by veins of quartz, but of particular interest in the present connection are the abundant veins of albite. Natrolite, so far as known to the writer, has not been found under these conditions except at the benitoite locality, but the analogous albite veins are very common.

Titanium is often found in the recrystallized rock, occasion- ally in the veins, and occurs most commonly as titanite, some- times as rutile.

While minerals containing potassium (usually muscovite), magnesium and iron (such as chlorite or more rarely talc) are also found in veins cutting such rocks, an association represent- ing so man~ metallic elements in essential quantities as occur in the benitoite veins is exceptional: sodium, potassium, magnesium, iron, manganese, copper, aluminum, barium. With this variety it seems peculiar that calcium is practically absent within the veins proper. It is found generally in the veins in the schists as lawsonite or the amphiboles.

The occurrence of barium as an essential constituent is with- out precedent. The only barium mineral that the writer has found associated with such formations is barite in veins in the serpentine of Mt. Diablo. While suggestive of the presence and possible concentration of barium in such rocks, it is not an analogous occurrence.

Apart from the chemical differences, a comparison of the chief gangue materials, albite and natrolite, would indicate that

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