The wikipedia article on $LOGCFL$ says that it is situated between $NL$ and $AC^1$. I read this as $NL\subset LOGCFL\subset LOGCFL/poly=SAC^1\subset AC^1$, hence $NL\subset SAC^1$.
Obviously $L\subset NL$, so we get the nice summary $$NC^1\subset L \subset NL \subset SAC^1$$
But the statement $SAC^1=LOGCFL/poly$ makes me wonder, whether $NC^1\subset L$ or rather $$NC^1\subset L/poly \subset NL/poly \subset SAC^1$$
Honestly, I'm really unsure now. So I googled a bit, and found lecture notes introducing Boolean circuits with even more doubtful statements
The usual convention is not to count "not" gates in either of the above: one can show that all the "not" gates of a circuit can be pushed to immediately follow the input gates; thus, ignoring "not" gates affects the size by at most $n$ and the depth by at most $1$.
I heavily doubt that this statement is "exactly" true. I feel reminded of the wikipedia article on Fagin's lemma, and similar "sloppy CS statements". But how am I supposed to read such sloppy statements, and how can I guess what they are intended to mean?