Here are the data structures with brief descriptions:

CAboutTab
CActionInitialization	Action initialization class
Caopt
CasciiField
CBGParts
CBMT_HitProcess
Cbmt_strip
CbmtConstants
Cbonus_HitProcess
Cbst_HitProcess
Cbst_strip
Cbubble_HitProcess
Ccamera_control
Cclara_det_factory
Ccnd_HitProcess
Ccormo_HitProcess
Ccpp_materials
Ccrs_HitProcess
Cctof_HitProcess
CctofConstants
CCVRT_HitProcess
Cdc_HitProcess
CdcConstants
CdescriptionTab
Cdetector
Cdetector_tree
CdetectorCondition
CdetectorFactory
Cec_HitProcess
CECAL_HitProcess
CecConstants
Cecs_HitProcess
CecsConstants
Cevio_output
CfieldFactory
Cflux_HitProcess
CFMT_HitProcess
Cfmt_strip
Cft_cal_HitProcess
Cft_hodo_HitProcess
CFTM_HitProcess
Cftm_strip
Cftof_HitProcess
CftofConstants
Cg4dialog
CG4MagneticField
CG4UImessenger
CG4UserEventAction
CG4UserSteppingAction
CG4VHit
CG4VModularPhysicsList
CG4VSensitiveDetector
CG4VUserActionInitialization
CG4VUserDetectorConstruction
CG4VUserPrimaryGeneratorAction
CgBank
Cgcoord
Cgdml_det_factory
Cgdml_materials
CgemcMainWidget
CgeneratedParticle
Cgfield
CglogicV
CgMappedField
Cgoperation
Cgoptions
Cgparticle
CgphysV
Cgposition
Cgraph
Cgrotation
Cgsignal
Cgsolid
Cgtable
Cgtrigger
Cgui_splash
ChitOutput
CHitProcess
Chtcc_HitProcess
CIC_HitProcess
Cidentifier
Cinfos
Cltcc_HitProcess
ClumiEvent
CLUNDTab
Cmaterial
Cmaterials
CMDetectorConstruction
CMDetectorMessenger
CMEventAction
CMHit
Cmirror
Cmirrors
CmomControls
CMPrimaryGeneratorAction
CMSteppingAction
CmultipoleField
Cmuon_hodo_HitProcess
Cmysql_det_factory
Cmysql_materials
Cmysql_mirrors
Cmysql_parameters
Coptions
CoutputContainer
CoutputFactory
CparametersFactory
CparticleTab
Cpcal_HitProcess
CpcConstants
CPColorsTab
CphysicsList
CPhysicsList
CPhysicsListMessenger
CQGraphicsView
CQWidget
Crich_HitProcess
Crun_control
CrunConditions
CrunWeights
CsensitiveDetector
CsensitiveID
CsummaryForParticle
CSVT_HitProcess
Ctext_det_factory
Ctext_materials
Ctext_mirrors
Ctext_parameters
CTInfos
Ctree_item
CtrueInfos
Ctxt_output
Cveto_HitProcess
CvtxControls