Take a look at this excerpt form Mussorgsky's Pictures at an Exposition.
Three questions arose:
1) According to books, the English horn is written 5th higher than heard. Since we are in the key of G# minor, isn't it supposed to be written in D# minor?
2) The clarinet is written in B minor, which is a minor third higher than G# minor. So I guess the clarinets are Eb clarinets. But the bass clarinets are also written in B minor. How come the books don't talk about Eb bass clarinets? On Finale, you have Eb clarinets but no Eb bass clarinets.
3) What the hell is that chord??
I appreciate your help.