Generation of broadband frequency combs in microring resonators provides an attractive tool for many practical applications, where a miniature source of broadband, regularly spaced spectral lines is required. Typical experiments on microresonator combs have been performed with silicon nitride and silica glass rings. Four-wave mixing and soliton formation are the most important building blocks of microresonator combs, which can be linked to the supercontinuum generation in photonic crystal fibers. In this talk I will discuss the influence of Raman scattering and higher order dispersions on solitons and frequency comb generation in silica microring resonators. The Raman effect introduces a threshold value in the resonator quality factor above which the frequency-locked solitons cannot exist, and instead, a rich dynamics characterized by generation of self-frequency-shifting solitons and dispersive waves is observed.