  We analyze the confident binary black hole (BBH) detections from the third
Gravitational-Wave Transient Catalog (GWTC-3) with an alternative mass
population model in order to capture features in the mass distribution beyond
the Powerlaw + Peak model. We find that the peak of a second power law
characterizes the $\sim 30-35~ M_\odot$ bump, such that the data marginally
prefers a mixture of two power laws for the mass distribution of binary
components over a Powerlaw + Peak model with a Bayes Factor
$\log_{10}\mathcal{B}$ of 0.1. This result may imply that the $\sim 30-35~
M_\odot$ feature represents the onset of a second population of BBH mergers
(e.g. from a dynamical formation channel) rather than a specific mass feature
over a broader distribution. When an additional Gaussian bump is allowed within
our power law mixture model, we find a new feature in the BH mass spectrum at
$\sim65-70~M_\odot$. This new feature may be consistent with hierarchical
mergers, and constitute $\sim2\%$ of the BBH population. This model also
recovers a maximum mass of $58^{+30}_{-14}~M_\odot$ for the second power law,
consistent with the onset of a pair-instability supernova mass gap.
