To all the public I was become recognizably old, undeniably old

Question

1. To all the public I was become recognizably old, undeniably old. 2. I now believe what Choate said last March, and which at the time I didn't credit.

I think these two sentences above are grammatically incorrect, but the fact that they are excerpts from a classic book makes me hesitate to say that. I would like to make sure I am on the right track. Please read the following, and enlighten me if I am wrong.

In 1) the verb should be just "became", not "was become".
In sentence 2) "and" preceding which should be out.

Answer 1

The extract is from 'Chapters from My Autobiography' Mark Twain (published 1906-1907).

The form using the verb 'to be' followed by a past participle - I am gone, he is come, I was become, etc is correct but obsolete or archaic since about 1900.

I consider that 'what Choate said to me last March', can be a defining clause (it distinguishes what he said last March from things he said at other times) and "which at the time I didn't credit" to be merely a comment, so the 'and' should be removed.

We can use and before the which/where/who etc introducing a subordinate clause, to co-ordinate them, when both are defining clauses or both are non-defining:

Correct (both are non-defining): A few minutes brought us to a large and busy bazaar, with the localities of which the stranger appeared well acquainted, and where his original demeanour again became apparent.—Poe.

Correct (both are defining): All the toys that infatuate men, and which they play for, are the self-same thing.—Emerson.

Correct (both are non-defining): Mr. Lovelace has seen divers apartments at Windsor; but not one, he says, that he thought fit for me, and which, at the same time, answered my description.

Incorrect (the first defines, the second does not): The hills were so broken and precipitous as to afford no passage except just upon the narrow line of the track which we occupied, and which was overhung with rocks.

Incorrect (the first defines, the second and third do not): And here he said in German what he wished to say, and which was of no great importance, and which I translated into English.

Incorrect (The first clause defines, the second is obviously one of comment: the 'scene' is not distinguished from those that the leader did take steps to avert): From doing this they were prevented by the disgraceful scene which took place, and which the leader of the Opposition took no steps to avert. (The Times)

See H.W. Fowler (1858–1933). The King’s English, 2nd ed. 1908.

Relevant chapter: http://www.bartleby.com/116/206.html

Fowler quotes a number of famous authors who have misused 'and which', and says: "A coordination in which 'and' is the natural conjunction may also be indicated simply by a comma; there is safety in this course."